Terminal apparatus, session management entity (SME), and communication control method

ABSTRACT

To provide a communication control means for establishing a session between a terminal apparatus and a network in a network-initiated manner and/or a connection control means for supporting service continuity and/or a session establishment control means for supporting service continuity and/or a communication control means for service continuity, and the like. These provide a communication control method for establishing an optimal session for service continuity through which service is continued by switching between sessions for communication, an optimal communication control method for service continuity, and the like.

TECHNICAL FIELD

The present invention relates to a terminal apparatus, a SessionManagement Entity (SME), and a communication control method. Thisapplication claims priority based on JP 2016-98568 filed on May 17, 2016in Japan, the contents of which are incorporated herein in its entiretyby reference.

BACKGROUND ART

The 3rd Generation Partnership Project (3GPP), which undertakesactivities for standardizing recent mobile communication systems,discusses System Architecture Enhancement (SAE), which is systemarchitecture of the Long Term Evolution (LTE). 3GPP is in the process ofcreating specifications for the Evolved Packet System (EPS) as acommunication system for realizing an all-IP architecture. Note that acore network constituting EPS is called an Evolved Packet Core (EPC).

In addition, recently, the 3GPP has also been conducting a study onnext-generation communication technologies and system architectures ofthe 5G (5th Generation) mobile communication system, which is a nextgeneration communication system. As a study on a next-generationcommunication technology, a study on NextGen (Architecture for NextGeneration System) has been conducted. In NextGen, technical problemsfor connecting various terminals to a cellular network are extracted,and solutions are standardized.

For example, optimization and diversification of a communicationprocedure for supporting a continuous mobile communication service,optimization of a system architecture according to the optimization anddiversification of the communication procedure, and the like for variousterminals are proposed as requirements.

CITATION LIST Non Patent Literature

-   NPL 1: 3rd Generation Partnership Project; Technical Specification    Group Services and System Aspects; Study on Architecture for Next    Generation System; (Release 14)

SUMMARY OF INVENTION Technical Problem

In NextGen, a study on optimization of session management in a mobilecommunication service between a terminal and a network apparatus hasbeen conducted.

More specifically, a study has been conducted to provide a continuousmobile communication service suitable for a terminal and a networkapparatus through diversification of a session establishment procedureand granularity of continuity of the mobile communication service.

However, a means for establishing a session, a means for enablingcontinuity of an optimized mobile communication service, and the likefor various terminals and network apparatuses have not been proposed.

The present invention has been made in view of such a circumstance, andan object of the present invention is to provide a means for sessionestablishment, a communication control means for enabling continuity ofan optimized mobile communication service, and the like. An object ofthe present invention is to provide a communication control means forproviding mobility suitable for a terminal and a communication path.

Solution to Problem

A terminal apparatus according to the present invention includes: acontroller configured to establish a first session associated with afirst IP address with a first gateway, based on a first sessionestablishment procedure, wherein the controller establishes a secondsession associated with a second IP address with a second gateway, basedon a second session establishment procedure, first identificationinformation is information acquired from a core network and informationindicating whether the first session is to be released, based on servicecontinuity switching communication in the first session to the secondsession, the controller continues the communication by switching thecommunication in the first session to the second session, and thecontroller releases the first session in a case that the firstidentification information indicates that the first session is to bereleased, and maintains the first session in a case that the firstidentification information indicates that the first session is not to bereleased, based on switching of the communication from the first sessionto the second session.

A Session Management Entity (SME) according to the present inventionincludes: a transmission and/or reception unit configured to transmit acontrol message including at least first identification information to aterminal apparatus, wherein the first identification information isinformation indicating whether a first session is to be released, basedon service continuity switching communication in the first session to asecond session, the first session is a session established between theterminal apparatus and a first gateway, based on a first sessionestablishment procedure, and the second session is a session establishedbetween the terminal apparatus and a second gateway, based on a secondsession establishment procedure.

A communication control method for a terminal apparatus according to thepresent invention includes the steps of: establishing a first sessionassociated with a first IP address with a first gateway, based on afirst session establishment procedure; and establishing a second sessionassociated with a second IP address with a second gateway, based on asecond session establishment procedure, first identification informationbeing information acquired from a core network and informationindicating whether the first session is to be released, based on servicecontinuity switching communication in the first session to the secondsession; switching the communication in the first session to the secondsession; and releasing the first session in a case that the firstidentification information indicates that the first session is to bereleased, and maintaining the first session in a case that the firstidentification information indicates that the first session is not to bereleased, based on switching of the communication from the first sessionto the second session.

A communication control method for a Session Management Entity (SME)according to the present invention includes the step of: transmitting acontrol message including at least first identification information to aterminal apparatus, wherein the first identification information isinformation indicating whether a first session is to be released, basedon service continuity switching communication in the first session to asecond session, the first session is a session established between theterminal apparatus and a first gateway, based on a first sessionestablishment procedure, and the second session is a session establishedbetween the terminal apparatus and a second gateway, based on a secondsession establishment procedure.

Advantageous Effects of Invention

According to the present invention, it is possible for a terminal toestablish a session under the initiative of the network and also toestablish connectivity according to continuity of an optimized mobilecommunication service. Moreover, it is possible for the core network toestablish a session under the initiative of the network and also toestablish a communication path according to continuity of an optimizedmobile communication service.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an overview of a mobile communicationsystem.

FIGS. 2A and 2B are diagrams illustrating an example of a configurationof a mobile communication network and the like.

FIGS. 3A and 3B are diagrams illustrating an example of a configurationof the mobile communication network and the like.

FIG. 4 is a diagram illustrating a PDU session established state.

FIG. 5 is a diagram illustrating an apparatus configuration of a UE.

FIGS. 6B to 6D are diagrams illustrating a storage unit of the UE.

FIG. 7 is a diagram illustrating an apparatus configuration of an eNB.

FIG. 8A is a diagram illustrating an apparatus configuration of a 5GBS.

FIG. 9A is a diagram illustrating an apparatus configuration of a WAG.

FIGS. 10A and 10B are diagrams illustrating an apparatus configurationof a SCEF.

FIG. 11A is a diagram illustrating an apparatus configuration of a MME.

FIG. 12B is a diagram illustrating a storage unit of the MME.

FIGS. 13C and 13D are diagrams illustrating the storage unit of the MME.

FIG. 14A is a diagram illustrating an apparatus configuration of a SGW.

FIGS. 15B to 15D are diagrams illustrating a storage unit of the SGW.

FIG. 16A is a diagram illustrating an apparatus configuration of a PGW.

FIGS. 17B to 17E are diagrams illustrating a storage unit of the PGW.

FIG. 18 is a diagram illustrating an overview of a communicationprocedure.

FIG. 19 is a diagram illustrating an attach procedure.

FIG. 20 is a diagram illustrating a UE-initiated PDU sessionestablishment procedure.

FIG. 21 is a diagram illustrating a first network-initiated PDU sessionestablishment procedure.

FIG. 22 is a diagram illustrating a second network-initiated PDU sessionestablishment procedure.

FIG. 23 is a diagram illustrating a UE-initiated flow switchingprocedure.

FIG. 24 is a diagram illustrating a network-initiated flow switchingprocedure.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a preferred embodiment for carrying out the presentinvention will be described with reference to the drawings. Note that asan example, the present embodiment describes an embodiment of a mobilecommunication system to which the present invention is applied.

1. System Overview

FIG. 1 is a diagram illustrating an overview of a mobile communicationsystem according to the present embodiment. As illustrated in FIG. 1, amobile communication system 1 includes a mobile terminal apparatus UE_A10, an access network, a core network_A 90, and a PDN_A 5.

Here, the UE_A 10 may be any wirelessly connectable terminal apparatus,and may be a User equipment (UE), a Mobile equipment (ME), or a MobileStation (MS).

The UE_A 10 may be a Cellular Internet of Things (CIoT) terminal. Notethat the CIoT terminal may be an Internet of Things (IoT) terminalconnectable with the core network_A 90, and the IoT terminal may includea mobile phone terminal such as a smartphone and may be any of variousIT devices such as a personal computer and a sensor device.

Here, the core network_A 90 refers to an IP mobile communication networkrun by a Mobile Operator.

For example, the core network_A 90 may be a core network for the mobileoperator that runs and manages the mobile communication system 1, or maybe a core network for a virtual mobile operator such as a Mobile VirtualNetwork Operator (MVNO). Alternatively, the core network_A 90 may be acore network for accommodating the CIoT terminal.

Furthermore, the access network may be a 3GPP access network or may be anon-3GPP access network.

The 3GPP access network may be a Long Term Evolution (LTE) AccessNetwork (LTE AN)_A 80, an Evolved Universal Terrestrial Radio AccessNetwork (E-UTRAN), a UMTS Terrestrial Radio Access Network (UTRAN)_A 20,a GSM EDGE Radio Access Network (GERAN)_A 25, or a 5G Radio AccessNetwork (RAN) 120, and the non-3GPP access network may be a WLAN ANb 75,a WLAN ANa 70, or a WLAN ANc 125.

The UE_A 10 connects to the core network_A 90 via the access network.

Additionally, the core network_A 90 is connected to the PDN_A 5. ThePDN_A 5 is a Data Network (DN) which provides a communication service tothe UE_A 10, and the DN, as a packet data service network, may beconfigured for each service. A communication terminal is connected tothe PDN, the UE_A 10 can transmit and/or receive user data to/from thecommunication terminal located in the PDN_A 5. Note that the user datamay be data transmitted and/or received between the UE_A 10 and anapparatus included in the PDN_A 5. The UE_A 10 transmits the user datato the PDN_A 5 via the core network_A 90. In other words, the UE_A 10transmits and/or receives the user data to and/or from the corenetwork_A 90, to transmit and/or receive the user data to and/or fromthe PDN_A 5. More specifically, the UE_A 10 transmits and/or receivesthe user data to and/or from a gateway device in the core network_A 90,such as a PGW_A 30, and a gateway device such as a SCEF_A 46, totransmit and/or receive the user data to and/or from the PDN_A 5. Thecommunication of user data may be non-IP communication without beinglimited to IP communication.

Next, examples of a configuration of the core network_A 90 will bedescribed. In the present embodiment, two configuration examples of thecore network_A 90 will be described.

FIGS. 2A and 2B illustrate an example of the configuration of the corenetwork_A 90. The core network_A 90 in FIG. 2A includes a HomeSubscriber Server (HSS)_A 50, an Authentication, Authorization,Accounting (AAA)_A 55, a Policy and Charging Rules Function (PCRF)_A 60,a Packet Data Network Gateway (PGW)_A 30, an enhanced Packet DataGateway (ePDG)_A 65, a Serving Gateway (SGW)_A 35, a Mobility ManagementEntity (MME)_A 40, a Serving GPRS Support Node (SGSN)_A 42, and aServing Capability Exposure Function (SCEF)_A 46.

Furthermore, the core network_A 90 is capable of connecting to multipleradio access networks (an LTE AN_A 80, a WLAN ANb 75, a WLAN ANa 70, aUTRAN_A 20, and a GERAN_A 25).

Such a radio access network may be configured by connecting to multipledifferent access networks, or may be configured by connecting to eitherone of the access networks. Moreover, the UE_A 10 is capable ofwirelessly connecting to the radio access network.

Moreover, a Wireless Local Area Network (LAN) (WLAN) Access Network b(WLAN ANb 75) that connects to the core network via the ePDG_A 65 and aWLAN Access Network a (WLAN ANa 70) that connects to the PGW_A 30, thePCRF_A 60, and the AAA_A 55 can be configured as access networksconnectable in a WLAN access system.

Note that each device has a similar configuration to those of thedevices of the related art in a mobile communication system using EPS,and thus detailed descriptions thereof will be omitted. Each device willbe described briefly hereinafter.

The PGW_A 30 is connected to the PDN_A 5, the SGW_A 35, the ePDG_A 65,the WLAN ANa 70, the PCRF_A 60, and the AAA_A 55, and serves as a relaydevice configured to transfer user data by functioning as a gatewaydevice between the PDN_A 5 and/or the Data Network (DN) and the corenetwork_A 90. Note that the PGW_A 30 may be a gateway device for IPcommunication and/or non-IP communication. Further, the PGW_A 30 mayhave a function of transferring IP communication and/or may have afunction of changing between non-IP communication and IP communication.Multiple gateways thus configured may be provided in the core network_A90. Further, multiple gateways configured to connect the core network_A90 and a single DN may be provided.

Here, the IP communication is data communication using Internet Protocol(IP) and is data communication performed by transmission and/orreception of an IP packet to which an IP header is attached. Note that apayload part constituting the IP packet may include user data to betransmitted from and/or received by the UE_A 10.

The non-IP communication is data communication not using InternetProtocol (IP) and is data communication performed by transmission and/orreception of data to which no IP header is attached. For example, thenon-IP communication may be data communication performed by transmissionand/or reception of application data to which no IP packet is attachedor may transmit and/or receive user data transmitted from and/orreceived by the UE_A 10 by attaching another header, such as a MACheader or an Ethernet (trade name) frame header.

The SGW_A 35 is connected to the PGW 30, the MME_A 40, the LTE AN_A 80,the SGSN_A 42, and the UTRAN_A 20, and serves as a relay deviceconfigured to transfer user data by functioning as a gateway devicebetween the core network_A 90 and the 3GPP access network (the UTRAN_A20, the GERAN_A 25, the LTE AN_A 80).

The MME_A 40 is connected to the SGW_A 35, the LTE AN_A 80, the HSS_A50, and the SCEF_A 46 and serves as a control apparatus configured toperform location information management, which includes mobilitymanagement and access control of the UE_A 10 through the LTE AN_A 80.Furthermore, the MME_A 40 may have a function as a session managementdevice configured to manage sessions established by the UE_A 10.Multiple control apparatuses thus configured may be provided in the corenetwork_A 90. For example, a location management device different fromthe MME_A 40 may be configured. As with the MME_A 40, the locationmanagement device different from the MME_A 40 may be connected to theSGW_A 35, the LTE AN_A 80, and the HSS_A 50.

Furthermore, in a case that multiple MMEs are included in the corenetwork_A 90, the MMEs may be connected to each other. With thisconfiguration, the context of the UE_A 10 may be transmitted and/orreceived between the MMEs.

The MME_A 40 is a management device configured to transmit and/orreceive control information associated with mobility management andsession management to and from the UE_A 10. In other words, the MME_A 40may be any control apparatus in a control plane. Moreover, a descriptionhas been given of an example in which the MME_A 40 is included in thecore network 90. However, in a case that the multiple core networks andnetwork slices are configured, the MME_A 40 may be a management deviceconnected to one or more core networks or may be a management deviceconnected to multiple network slices.

The multiple core networks or network slices may be networks run by asingle network operator or may be networks run by different networkoperators. Here, the network slices may be logical networks configuredto classify user data delivered through a service and the like.

The HSS_A 50 is connected to the MME_A 40, the AAA_A 55, and the SCEF_A46 and serves as a managing node that manages subscriber information.The subscriber information of the HSS_A 50 is referred to during MME_A40 access control, for example. Moreover, the HSS_A 50 may be connectedto the location management device different from the MME_A 40.

The AAA_A 55 is connected to the PGW 30, the HSS_A 50, the PCRF_A 60,and the WLAN ANa 70, and is configured to perform access control for theUE_A 10 connected via the WLAN ANa 70.

The PCRF_A 60 is connected to the PGW_A 30, the WLAN ANa 75, the AAA_A55, and the PDN_A 5, and is configured to perform QoS management on datadelivery. For example, the PCRF_A 60 manages QoS of a communication pathbetween the UE_A 10 and the PDN_A 5.

The cPDG_A 65 is connected to the PGW 30 and the WLAN ANb 75 and isconfigured to deliver user data by functioning as a gateway devicebetween the core network_A 90 and the WLAN ANb 75.

The SGSN_A 42 is connected to the UTRAN_A 20, the GERAN_A 25, and theSGW_A 35 and is a control apparatus for location management between a3G/2G access network (UTRAN/GERAN) and the LTE access network (E-UTRAN).In addition, the SGSN_A 42 has functions of: selecting the PGW and theSGW; managing a time zone of the UE; and selecting the MME at the timeof handover to the E-UTRAN.

The SCEF_A 46 is connected to the PDN_A 5, the MME_A 40, and the HSS_A50 and is a relay device configured to transfer user data as a gatewaydevice connecting the PDN_A 5 and/or the Data Network (DN) and the corenetwork_A 90. Note that the SCEF_A 46 may be a gateway device for non-IPcommunication. Further, the SCEF_A 46 may have a function of changingbetween non-IP communication and IP communication. Multiple gatewaysthus configured may be arranged in the core network_A 90. Further,multiple gateways configured to connect the core network_A 90 and asingle DN may be arranged.

Additionally, as illustrated in FIG. 2B, each radio access networkincludes apparatuses to which the UE_A 10 is actually connected (such asa base station apparatus and an access point device), and the like. Theapparatuses used in these connections can be thought of as apparatusesadapted to the radio access networks.

In the present embodiment, the LTE AN_A 80 includes the eNB_A 45. TheeNB_A 45 is a radio base station to which the UE_A 10 connects in an LTEaccess system, and the LTE AN_A 80 may include one or multiple radiobase stations.

The WLAN ANa 70 includes a WLAN APa 72 and a TWAG_A 74. The WLAN APa 72is a radio base station (WLAN Access Point (WLAN AP)) to which the UE_A10 connects in the WLAN access system trusted by the operator runningthe core network_A 90, and the WLAN ANa 70 may include one or multipleradio base stations. The TWAG_A 74 serves as a gateway device (TrustedWLAN Access Gateway (TWAG) between the core network_A 90 and the WLANANa 70. The WLAN APa 72 and the TWAG_A 74 may be configured as a singledevice.

Even in a case that the operator running the core network_A 90 and theoperator running the WLAN ANa 70 are different, such a configuration canbe implemented through contracts and agreements between the operators.

Furthermore, the WLAN ANb 75 is configured to include a WLAN APb 76. TheWLAN APb 76 is a radio base station to which the UE_A 10 connects in theWLAN access system in a case that no trusting relationship isestablished with the operator running the core network_A 90, and theWLAN ANb 75 may include one or multiple radio base stations.

In this manner, the WLAN ANb 75 is connected to the core network_A 90via the ePDG_A 65, which is a device included in the core network_A 90,serving as a gateway. The ePDG_A 65 has a security function for ensuringsecurity.

The UTRAN_A 20 includes a Radio Network Controller (RNC)_A 24 and an eNB(UTRAN)_A 22. The eNB (UTRAN)_A 22 is a radio base station to which theUE_A 10 connects through a UMTS Terrestrial Radio Access (UTRA), and theUTRAN_A 20 may include one or multiple radio base stations. Furthermore,the RNC_A 24 is a controller configured to connect the core network_A 90and the eNB (UTRAN)_A 22, and the UTRAN_A 20 may include one or multipleRNCs. Moreover, the RNC_A 24 may be connected to one or multiple eNBs(UTRANs)_A 22. In addition, the RNC_A 24 may be connected to a radiobase station (Base Station Subsystem (BSS)_A 26) included in the GERAN_A25.

The GERAN_A 25 includes the BSS_A 26. The BSS_A 26 is a radio basestation to which the UE_A 10 connects through GSM (trade name)/EDGERadio Access (GERA), and the GERAN_A 25 may be constituted of one ormultiple radio base station BSSs. Furthermore, the multiple BSSs may beconnected to each other. Moreover, the BSS_A 26 may be connected to theRNC_A 24.

Next, a second example of a configuration of the core network_A 90 willbe described. FIG. 3A illustrates an example of the configuration of thecore network_A 90. The core network_A 90 in FIG. 2A includes the HomeSubscriber Server (HSS)_A 50, the Policy and Charging Rules Function(PCRF)_A 60, the Packet Data Network Gateway (PGW)_A 30, the ServingGateway (SGW)_A 35, the Mobility Management Entity (MME)_A 40, and theServing Capability Exposure Function (SCEF)_A 46.

Furthermore, the core network_A 90 can connect to multiple radio accessnetworks (E-UTRAN, the 5G RAN 120, and the WLAN ANc 125).

Such a radio access network may be configured by connecting to multipledifferent access networks, or may be configured by connecting to eitherone of the access networks. Moreover, the UE_A 10 is capable ofwirelessly connecting to the radio access network.

Moreover, the E-UTRAN and the 5G RAN 120 can be configured as accessnetworks connectable in a 3GPP access system.

Moreover, a WLAN access network c (WLAN ANc 125) connecting to the MME_A40 and the SGW_A 35 can be configured as an access network connectablein a WLAN access system.

Note that each apparatus has a similar configuration to those of thedevices of the related art in a mobile communication system using EPS,and thus detailed descriptions thereof will be omitted. Each device willbe described briefly hereinafter.

The SGW_A 35 is connected to the PGW_A 30, the MME_A 40, the E-UTRAN,the 5G RAN 120, and the WLAN ANc 126, and is a relay device configuredto transfer user data by functioning as a gateway device between thecore network_A 90 and the 3GPP access network (the E-UTRAN and the 5GRAN 120) and/or the non-3GPP access network (WLAN ANc 126).

The MME_A 40 is connected to the SGW_A 35, the E-UTRAN, the 5G RAN 120,the WLAN ANc 126, the HSS_A 50, and the SCEF_A 46, and is an accesscontrol apparatus configured to perform location information managementand access control of the UE_A 10 via the 3GPP access network and/or thenon-3GPP access network. Furthermore, the core network_A 90 may includemultiple location management devices. For example, a location managementdevice different from the MME_A 40 may be configured. As with the MME_A40, the location management device different from the MME_A 40 may beconnected to the SGW_A 35, the E-UTRAN, the 5G RAN 120, the WLAN ANc126, and the HSS_A 50.

The MME_A 40 may be a relay device configured to transfer user data byfunctioning as a gateway device between the core network_A 90 and the3GPP access network (the E-UTRAN and the 5G RAN 120) and/or the non-3GPPaccess network (WLAN ANc 126). Note that the user data transmittedand/or received via the MME_A 40 serving as a gateway device may besmall data. Moreover, in a case that multiple MMEs are included in thecore network_A 90, the MMEs may be connected to each other. With thisconfiguration, the context of the UE_A 10 may be transmitted and/orreceived between the MMEs.

Note that the PGW_A 30, the SCEF_A 46, the HSS_A 50, and the PCRF_A 60may be devices similar to those described in FIGS. 2A and 2B. Therefore,description of the devices will be omitted.

Additionally, as illustrated in FIG. 3B, each radio access networkincludes apparatuses to which the UE_A 10 is actually connected (such asa base station apparatus and an access point apparatus), and the like.The apparatuses used in these connections can be thought of asapparatuses adapted to the radio access networks.

In the present embodiment, the E-UTRAN includes the eNB_A 45. The eNB_A45 is a radio base station to which the UE_A 10 connects in the E-UTRAN,and the E-UTRAN may include one or multiple radio base stations.

The 5G RAN 120 is an access network used in 5G mobile communication. The5G RAN 120 includes a 5GBS_A 122. The 5GBS_A 122 is a radio base station(5G Base Station (5GBS) to which the UE_A 10 connects in the 5G RAN 120,and the 5G RAN 120 may include one or multiple radio base stations.

The WLAN ANc 125 includes a WAG_A 126. The WAG_A 126 is a radio basestation (WLAN Access Gateway (WAG) to which the UE_A 10 connects, andthe WLAN ANc 125 may include one or multiple radio base stations.Furthermore, the WAG_A 126 may be a gateway device between the corenetwork_A 90 and the WLAN ANc 125. Moreover, in the WAG_A 126, afunction unit as a radio base station and a function unit as a gatewaydevice may be configured by different apparatuses.

A first core network and/or a second core network may be constituted bya system optimized for IoT.

Note that herein, the UE_A 10 being connected to radio access networksrefers to the UE_A 10 being connected to a base station apparatus, anaccess point, or the like included in each of the radio access networks,and data, signals, and the like being transmitted and/or received alsopass through those base station apparatuses, access points, or the like.

1.2. Apparatus Configuration

The configuration of each apparatus will be described below.

1.2.1. Configuration of UE

FIG. 5 illustrates an apparatus configuration of the UE_A 10. Asillustrated in FIG. 5, the UE_A 10 comprises a transmission and/orreception unit_A 520, a controller_A 500, and a storage unit_A 540. Thetransmission and/or reception unit_A 520 and the storage unit_A 540 areconnected to the controller_A 500 via a bus.

The controller_A 500 is a function unit for controlling the UE_A 10. Thecontroller_A 500 implements various processes by reading out variousprograms stored in the storage unit_A 540 and performing the programs.

The transmission and/or reception unit_A 520 is a function unit throughwhich the UE_A 10 connects to a base station and/or an access point inan access network to connect to the access network. Furthermore, anexternal antenna_A 510 is connected to the transmission and/or receptionunit_A 520.

In other words, the transmission and/or reception unit_A 520 is afunction unit through which the UE_A 10 connects to the base stationand/or the access point in the access network. Moreover, thetransmission and/or reception unit_A 520 is a transmission and/orreception function unit through which the UE_A 10 transmits and/orreceives user data and/or control data from the base station and/or theaccess point in the access network.

The storage unit_A 540 is a function unit for storing programs, data,and the like necessary for each operation of the UE_A 10. The storage_A540 is constituted of, for example, a semiconductor memory, a Hard DiskDrive (HDD), or the like.

The storage unit_A 540 may store at least identification informationand/or control information and/or a flag and/or a parameter included inthe control message transmitted and/or received in a communicationprocedure that will be described later.

As illustrated in FIG. 5, the storage unit_A 540 stores a UE context542. Hereinafter, information elements stored in the storage_A 540 willbe described.

First, FIG. 6B illustrates information elements included in the UEcontext stored for each UE. As illustrated in FIG. 6B, the UE contextstored for each UE includes IMSI, an EMM State, a GUTI, ME Identity, UEAccess Network Capability, NW Access Network Capability, andNetwork-initiated Session Establishment Capability.

The IMSI is permanent identification information of a subscriber.

The EMM State indicates a mobility management state of the UE. Forexample, the EMM State may be EMM-REGISTERED in which the UE isregistered with the network (registered state) or EMM-DEREGISTERD inwhich the UE is not registered with the network (deregistered state).

GUTI is an abbreviation of “Globally Unique Temporary Identity”, and istemporary identification information on the UE. The GUTI includes theidentification information about the MME (Globally Unique MME Identifier(GUMMEI)) and the identification information about the UE in a specificMME (M-TMSI).

The ME Identity is an ID of an ME, and may be the IMEI/IMISV, forexample.

The UE Access Network Capability is information indicating an accessnetwork to which the UE_A 10 is connectable. Here, the access networkmay be a 3GPP access network or may be a non-3GPP access network. The UEAccess Network Capability may include information indicating multipleaccess networks. In this case, the UE Access Network Capability mayfurther include information indicating priority levels of the accessnetworks together.

The NW Access Network Capability is information indicating an accessnetwork to which the core network_A 90 is connectable. The NW AccessNetwork Capability may include information indicating multiple accessnetworks. In this case, the NW Access Network Capability may furtherinclude information indicating priority levels of the access networks.

The Network-initiated Session Establishment Capability is informationindicating whether a network-initiated session establishment procedurecan be performed. The Network-initiated Session Establishment Capabilitymay be further classified into UE Network-initiated SessionEstablishment Capability indicating that the UE_A 10 allows thenetwork-initiated session establishment procedure and NWNetwork-initiated Session Establishment Capability indicating that thecore network_A 90 allows the network-initiated session establishmentprocedure.

Next, the UE context for each Packet Data Unit (PDU) session stored foreach PDU session is illustrated in FIG. 6C. As illustrated in FIG. 6C,the UE context for each PDU session includes APN in Use (Data NetworkIdentifier), an Assigned Session Type (Assigned PDN Type), an IPAddress, a Default Bearer, and a Mobility Type.

Note that the PDU session is a communication path established in orderfor the UE_A 10 and the core network_A 90 and/or the data network totransmit and/or receive user data. More specifically, the PDU session isa communication path for transmitting and/or receiving a PDU. The PDUsession may be a session established between the UE_A 10 and the corenetwork_A 90 and/or the Data Network (DN) or may be a logicalcommunication path constituted by a transfer path(s), such as one ormultiple bearers, between apparatuses in the mobile communication system1.

More specifically, the PDU session may be a connection established bythe UE_A 10 between the UE_A 10 and a gateway connecting the corenetwork_A 90 and the DN. Furthermore, the DN may be a Packet DataNetwork (PDN). Hence, the PDU session may be a connection such as a PDNconnection established between the UE_A 10 and the PGW_A 30. A device,such as an application server, provided between the UE_A 10 and the DNcan perform transmission and/or reception of user data by using the PDUsession. In other words, the PDU session can transfer user datatransmitted and/or received by the device, such as an applicationserver, provided between the UE_A 10 and the DN.

Moreover, the Access Point Name (APN) may be identification informationfor identifying the core network_A 90 or an external network, such as adata network. Further, the APN can also be used as information forselecting a gateway device, such as the PGW_A 30, that connects the corenetwork A_A 90. Note that the APN may be identification information foridentifying such a gateway device or may be identification informationfor identifying an external network, such as a data network. In a casethat multiple gateways that connect the core network_A 90 and the DN areprovided, there may be multiple gateways selectable based on the APN.Further, in a case that a single gateway is selected from among suchmultiple gateway devices, the gateway may be selected by anothertechnique using identification information other than the APN. The APNin Use (Data Network Identifier) is an APN recently utilized. This APNmay include identification information about the network andidentification information about a default operator. Moreover, the APNin Use (Data Network Identifier) may be information for identifying thedata network with which the PDU session is to be established.

The Assigned Session Type (Assigned PDN Type) is information indicatinga PDU session type. The PDU session type may be of IP type or non-IPtype. Moreover, in a case that the PDU session type is of IP type, theAssigned Session Type may further include information indicating the PDNtype assigned by the network. Note that the PDN type may be of IPv4type, IPv6 type, or IPv4v6 type.

The IP Address is an IP address allocated to the UE. The IP address maybe an IPv4 address, an IPv6 address, or an IPv6 prefix. Note that, in acase that the Assigned Session Type (Assigned PDN Type) indicatesnon-IP, the Assigned Session Type may not necessarily include any IPAddress element.

The Default Bearer is information acquired from the core network_A 90 atthe time of establishing a PDU session and is EPS bearer identificationinformation for identifying a default bearer associated with the PDUsession.

Note that the EPS bearer may be a logical communication path establishedbetween the UE_A 10 and the PGW_A 30. Also in this case, the EPS bearermay include a Radio Bearer (RB) established between the UE_A 10 and abase station and/or an access point in the access network. Further, theRB and the EPS bearer may be associated with each other in a one-to-onecorrespondence. Hence, identification information of the RB may beassociated with identification information of the EPS bearer in aone-to-one correspondence or may be the same as the identificationinformation of the EPS bearer. The RB may be a Signalling Radio Bearer(SRB) or a Data Radio Bearer (DRB).

The Mobility Type is information indicating the granularity of mobility.Further, the Mobility Type may be information indicating the type ofservice continuity.

FIG. 6D illustrates the UE context for each bearer stored in the storageunit of the UE. As illustrated in FIG. 6D, the UE context for eachbearer includes an EPS Bearer ID, a TI, a TFT, and a Radio Bearer Type.

The UE context for each bearer may include information for identifying acommunication path to be an efficient path.

The EPS Bearer ID is identification information of the EPS bearer. TheEPS Bearer ID may be identification information for identifying an SRBand/or a CRB or identification information for identifying a DRB.

The TI is an abbreviation of a “Transaction Identifier”, and isidentification information identifying a bidirectional message flow(Transaction).

The TFT is an abbreviation of a “Traffic Flow Template”, and indicatesall packet filters associated with the EPS bearer. In other words, theTFT is information for identifying part of user data to be transmittedand/or received, and the UE_A 10 transmits and/or receives the user dataidentified by the TFT by using the EPS bearer associated with the TFT.Stated further differently, the UE_A 10 transmits and/or receives theuser data identified by the TFT by using the RB associated with the TFT.

The TFT may associates user data, such as application data, to betransmitted and/or received with an appropriate transfer path or may beidentification information for identifying application data.

The UE_A 10 may transmit and/or receive user data that is notidentifiable based on the TFT, by using a default bearer.

The UE_A 10 may store in advance the TFT in association with a defaultbearer.

The Radio Bearer Type is information indicating a bearer type. Theinformation indicating the bearer type may be a DRB or a SRB.

1.2.2. Configuration of eNB

The configuration of the eNB_A 45 will be described below. FIG. 7illustrates an apparatus configuration of the eNB_A 45. As illustratedin FIG. 7, the eNB_A 45 comprises a network connection unit_B 720, atransmission and/or reception unit_B 730, a controller_B 700, and astorage unit_B 740. The network connection unit_B 720, the transmissionand/or reception unit_B 730, and the storage unit_B 740 are connected tothe controller_B 700 via a bus.

The controller_B 700 is a function unit for controlling the eNB_A 45.The controller_B 700 implements various processes by reading out andperforming various programs stored in the storage unit_B 740.

The network connection unit_B 720 is a function unit through which theeNB_A 45 connects to the MME_A 40 and/or the SGW_A 35. Furthermore, thenetwork connection unit_B 720 is a transmission and/or reception unitthrough which the eNB_A 45 transmits and/or receives the user dataand/or control data to and/or from the MME_A 40 and/or the SGW_A 35.

The transmission and/or reception unit_B 730 is a function unit throughwhich the eNB_A 45 connects to the UE_A 10. Furthermore, thetransmission and/or reception unit_B 730 is a transmission and/orreception function unit through which the eNB_A 45 transmits and/orreceives user data and/or control data to and/or from the UE_A 10.Furthermore, an external antenna_B 710 is connected to the transmissionand/or reception unit_B 730.

The storage unit_B 740 is a function unit for storing programs, data,and the like necessary for each operation of the eNB_A 45. The storageunit_B 740 is constituted of, for example, a semiconductor memory, aHard Disk Drive (HDD), or the like.

The storage unit_B 740 may store at least the identification informationand/or the control information and/or the flag and/or the parameterincluded in the control message transmitted and/or received in acommunication procedure that will be described later.

1.2.3. Configuration of 5GBS

A configuration of the 5GBS_A 122 will be described below. FIG. 8Aillustrates an apparatus configuration of the 5GBS_A 122. As illustratedin FIG. 8A, the 5GBS_A 122 comprises a network connection unit_C 820, atransmission and/or reception unit_C 830, a controller_C 800, and astorage unit_C 840. The network connection unit_C 820, the transmissionand/or reception unit_C 830, and the storage unit_C 840 are connected tothe controller_C 800 via a bus.

The controller_C 800 is a function unit for controlling the 5GBS_A 122.The controller_C 800 implements various processes by reading out andperforming various programs stored in the storage unit_C 840.

The network connection unit_C 820 is a function unit through which the5GBS_A 122 connects to the MME_A 40 and/or the SGW_A 35. Furthermore,the network connection unit_C 820 is a transmission and/or receptionunit through which the 5GBS_A 122 transmits and/or receives the userdata and/or control data to and/or from the MME_A 40 and/or the SGW_A35.

The transmission and/or reception unit_C 830 is a function unit throughwhich the 5GBS_A 122 connects to the UE_A 10. Furthermore, thetransmission and/or reception unit_C 830 is a transmission and/orreception function unit through which the 5GBS_A 122 transmits and/orreceives user data and/or control data to and/or from the UE_A 10.Moreover, an external antenna_C 810 is connected to the transmissionand/or reception unit_C 830.

The storage unit_C 840 is a function unit for storing programs, data,and the like necessary for each operation of the 5GBS_A 122. The storageunit_C 840 is constituted of, for example, a semiconductor memory, aHard Disk Drive (HDD), or the like.

The storage unit_C 840 may store at least the identification informationand/or the control information and/or the flag and/or the parameterincluded in the control message transmitted and/or received in acommunication procedure that will be described later.

1.2.4. Configuration of WAG

A configuration of the WAG_A 126 will be described below. FIG. 9Aillustrates an apparatus configuration of the WAG_A 126. As illustratedin FIG. 9A, the WAG_A 126 comprises a network connection unit_D 920, atransmission and/or reception unit_D 930, a controller_D 900, and astorage unit_D 940. The network connection unit_D 920, the transmissionand/or reception unit_D 930, and the storage unit_D 940 are connected tothe controller_D 900 via a bus.

The controller_D 900 is a function unit for controlling the WAG_A 126.The controller_D 900 implements various processes by reading out andperforming various programs stored in the storage unit_D 940.

The network connection unit_D 920 is a function unit through which theWAG_A 126 connects to the MME_A 40 and/or the SGW_A 35. Furthermore, thenetwork connection unit_D 920 is a transmission and/or reception unitthrough which the WAG_A 126 transmits and/or receives user data and/orcontrol data to and/or from the MME_A 40 and/or the SGW_A 35.

The transmission and/or reception unit_D 930 is a function unit throughwhich the WAG_A 126 connects to the UE_A 10. Furthermore, thetransmission and/or reception unit_D 930 is a transmission and/orreception function unit through which the WAG_A 126 transmits and/orreceives user data and/or control data to and/or from the UE_A 10.Furthermore, an external antenna D 910 is connected to the transmissionand/or reception unit_D 930.

The storage unit_D 940 is a function unit for storing programs, data,and the like necessary for each operation of the WAG_A 126. The storageunit_D 940 is constituted of, for example, a semiconductor memory, aHard Disk Drive (HDD), or the like.

The storage unit_D 940 may store at least the identification informationand/or the control information and/or the flag and/or the parameterincluded in the control message transmitted and/or received in acommunication procedure that will be described later.

1.2.5. Configuration of SCEF

FIG. 10A illustrates an apparatus configuration of the SCEF_A 46. Asillustrated in FIG. 10A, the SCEF_A 46 comprises a transmission and/orreception unit_E 1020, a controller_E 1000, and a storage unit_E 1040.The transmission and/or reception unit_E 1020 and the storage unit_E1040 are connected to the controller_E 1000 via a bus.

The controller_E 1000 is a function unit for controlling the SCEF_A 46.The controller_E 1000 implements various processes by reading out andperforming various programs stored in the storage unit_E 1040.

The transmission and/or reception unit_E 1020 is a function unit throughwhich the SCEF_A 46 connects to the core network_A 90. In other words,the transmission and/or reception unit_E 1020 is a function unit throughwhich the SCEF_A 46 connects to the MME_A 40. Furthermore, thetransmission and/or reception unit_E 1020 is a transmission and/orreception function unit through which the SCEF_A 46 transmits and/orreceives user data and/or control data to and/or from the MME_A 40.

The storage unit_E 1040 is a function unit for storing programs, data,and the like necessary for each operation of the SCEF_A 46. The storageunit_E 1040 is constituted of, for example, a semiconductor memory, aHard Disk Drive (HDD), or the like.

The storage unit_E 1040 may store at least the identificationinformation and/or the control information and/or the flag and/or theparameter included in the control message transmitted and/or received ina communication procedure that will be described later.

As illustrated in FIG. 10A, the storage unit_E 1040 stores an EPS bearercontext 1042. Hereinafter, information elements stored in the storageunit_E 1040 will be described.

FIG. 10B illustrates information elements included in each EPS bearercontext. As illustrated in FIG. 10B, the EPS bearer context includes aUser Identity, APN in Use (Data Network Identifier), an EPS Bearer ID,and Serving Node Information.

The User Identity is information for identifying a subscriber. The UserIdentity may be IMSI or may be MSISDN. Furthermore, the User Identitymay be identification information other than IMSI and MSISDN.

The APN in Use (Data Network Identifier) is an APN utilized. This APNmay include identification information about the network andidentification information about a default operator. Moreover, the APNin Use (Data Network Identifier) may be information for identifying thedata network with which the PDU session is to be established.

The EPS Bearer ID is identification information of the EPS bearer.

The Serving Node Information is an IP address of the MME_A 40 used inthe PDU session.

1.2.6. Configuration of MME

The configuration of the MME_A 40 will be described below. FIG. 11Aillustrates an apparatus configuration of the MME_A 40. As illustratedin FIG. 11A, the MME_A 40 comprises a network connection unit_F 1120, acontroller_F 1100, and a storage unit_F 1140. The network connectionunit_F 1120 and the storage unit_F 1140 are connected to thecontroller_F 1100 via a bus.

The controller_F 1100 is a function unit for controlling the MME_A 40.The controller_F 1100 implements various processes by reading out andperforming various programs stored in the storage unit_F 1140.

The network connection unit_F 1120 is a function unit through which theMME_A 40 connects to a base station in the access network and/or anaccess point in the access network and/or the SCEF_A 46 and/or the HSS_A50 and/or the SGW_A 35. Furthermore, the network connection unit_F 1120is a transmission and/or reception unit through which the MME_A 40transmits and/or receives user data and/or control data to and/or fromthe base station in the access network, and/or the access point in theaccess network, and/or the SCEF_A 46, the HSS_A 50, and/or the SGW_A 35.

The storage unit_F 1140 is a function unit for storing programs, data,and the like necessary for each operation of the MME_A 40. The storageunit_F 1140 is constituted of, for example, a semiconductor memory, aHard Disk Drive (HDD), or the like.

The storage unit_F 1140 may store at least the identificationinformation and/or the control information and/or the flag and/or theparameter included in the control message transmitted and/or received ina communication procedure that will be described later.

As illustrated in FIG. 11A, the storage_F 1140 stores a MME context1142. Hereinafter, information elements stored in the storage unit_F1140 will be described.

First, FIG. 12B illustrates information elements included in the UEcontext stored for each UE. As illustrated in FIG. 12B, the MME contextstored for each UE includes IMSI, MSISDN, a MM State, a GUTI, a MEIdentity, UE Radio Access Capability, UE Network Capability, MS NetworkCapability, Access Restriction, MME F-TEID, SGW F-TEID, a MME Address,an eNB Address, a MME UE S1AP ID, an eNB UE S1AP ID, a 5GBS Address, a5GBS ID, a WAG Address, a WAG ID, UE Access Network Capability, NWAccess Network Capability, and Network-initiated Session EstablishmentCapability.

The MME context for each UE may include information for identifying acommunication path to be an efficient path.

The IMSI is permanent identification information of a user. The IMSI isidentical to the IMSI stored in the HSS_A 50.

MSISDN represents the phone number of UE. The MSISDN is indicated by thestorage unit of the HSS_A 50.

The MM State indicates a Mobility management state of the MME. Thismanagement information indicates an ECM-IDLE state in which a connectionbetween the eNB and the core network is released, an ECM-CONNECTED statein which the connection between the eNB and the core network is notreleased, or an EMM-DEREGISTERED state in which the MME does not storethe location information of the UE.

The Globally Unique Temporary Identity (GUTI) is temporaryidentification information about the UE. The GUTI includes theidentification information about the MME (Globally Unique MME Identifier(GUMMEI)) and the identification information about the UE in a specificMME (M-TMSI).

The ME Identity is an ID of the UE, and may be the IMEI/IMISV, forexample.

The UE Radio Access Capability is identification information indicatinga radio access capability of the UE.

The UE Network Capability includes an algorithm of security supported bythe UE and a key derivative function.

The MS Network Capability is information including at least one kind ofinformation necessary for the SGSN to the UE having the GERAN and/orUTRAN function.

The Access Restriction is registration information for accessrestriction.

The MME F-TEID is information for identifying the MME_A 40. The MMEF-TEID may include an IP address of the MME_A 40 or may include a TunnelEndpoint Identifier (TEID) of the MME_A 40.

The SGW F-TEID is information for identifying the SGW_A 35. The SGWF-TEID may include the IP address of the SGW_A 35 or may include theTEID of the SGW_A 35.

The MME Address is the IP address of the MME_A 40.

The eNB Address is the IP address of the eNB_A 45.

The MME UE S1AP ID is information for identifying the UE in the MME_A40.

The eNB UE S1AP ID is information for identifying the UE in the eNB_A45.

The 5GBS Address is the IP address of the 5GBS_A 122.

The 5GBS ID is information for identifying the UE in the 5GBS_A 122.

The WAG Address is the IP address of the WAG_A 126.

The WAG ID is information for identifying the UE in the WAG_A 126.

The UE Access Network Capability is information indicating an accessnetwork to which the UE_A 10 is connectable. Here, the access networkmay be a 3GPP access network or may be a non-3GPP access network. The UEAccess Network Capability may include information indicating multipleaccess networks. In this case, the UE Access Network Capability mayfurther include information indicating priority levels of the accessnetworks together.

The NW Access Network Capability is information indicating an accessnetwork to which the core network_A 90 is connectable. The NW AccessNetwork Capability may include information indicating multiple accessnetworks. In this case, the NW Access Network Capability may furtherinclude information indicating priority levels of the access networks.

The Network-initiated Session Establishment Capability is informationindicating whether a network-initiated session establishment procedurecan be performed. The Network-initiated Session Establishment Capabilitymay be further classified into UE Network-initiated SessionEstablishment Capability indicating that the UE_A 10 allows thenetwork-initiated session establishment procedure and NWNetwork-initiated Session Establishment Capability indicating that thecore network_A 90 allows the network-initiated session establishmentprocedure.

Next, UE context for each PDU session stored for each PDU session isillustrated in FIG. 13C. As illustrated in FIG. 13C, the MME context foreach PDU session includes APN in Use (Data Network Identifier), anAssigned Session Type (Assigned PDN Type), an IP Address, a PGW F-TEID,a SCEF ID, and a Mobility Type.

The APN in Use (Data Network Identifier) is an APN recently utilized.This APN may include identification information about the network andidentification information about a default operator. Moreover, the APNin Use (Data Network Identifier) may be information for identifying thedata network with which the PDU session is to be established.

The Assigned Session Type (Assigned PDN Type) is information indicatinga PDU session type. The PDU session type may be of IP type or non-IPtype. Moreover, in a case that the PDU session type is of IP type, theAssigned Session Type may further include information indicating the PDNtype assigned by the network. Note that the PDN type may be of IPv4type, IPv6 type, or IPv4v6 type.

The IP Address is an IP address allocated to the UE. The IP address maybe an IPv4 address, an IPv6 address, or an IPv6 prefix. Note that, in acase that the Assigned Session Type (Assigned PDN Type) indicatesnon-IP, the Assigned Session Type may not necessarily include any IPAddress element.

The PGW F-TEID is information for identifying the PGW_A 30. The PGWF-TEID may include an IP address of the PGW_A 30 or may include a TEIDof the PGW_A 30.

The SCEF ID is the IP address of the SCEF_A 46 used in the PDU session.

The Default Bearer is information acquired and/or generated at the timeof establishing the PDU session and is EPS bearer identificationinformation for identifying the default bearer associated with the PDUsession.

The Mobility Type is information indicating the granularity of mobility.Further, the Mobility Type may be information indicating the type ofservice continuity.

FIG. 13D illustrates the MME context for each bearer stored for eachbearer. As illustrated in FIG. 13D, the MME context stored for eachbearer includes an EPS Bearer ID, a TI, a TFT, a SGW F-TEID, a PGWF-TEID, a MME F-TEID, an eNB/5GBS/WAG Address, an eNB/5GBS/WAG ID, and aRadio Bearer Type.

The EPS Bearer ID is the identification information for identifying theEPS bearer for a UE connection via the E-UTRAN.

Note that the EPS Bearer ID may be EPS bearer identification informationfor identifying a dedicated bearer. Hence, the EPS Bearer ID may beidentification information for identifying an EPS bearer different fromthe default bearer.

The TI is an abbreviation of a “Transaction Identifier”, and isidentification information identifying a bidirectional message flow(Transaction).

The TFT is an abbreviation of a “Traffic Flow Template”, and indicatesall packet filters associated with the EPS bearer.

The SGW F-TEID is information for identifying the SGW_A 35. The SGWF-TEID may include the IP address of the SGW_A 35 or may include theTunnel Endpoint Identifier (TEID) of the SGW_A 35.

The PGW F-TEID is information for identifying the PGW_A 30. The PGWF-TEID may include the IP address of the PGW_A 30 or may include theTEID of the PGW_A 30.

The MME F-TEID is information for identifying the MME_A 40. The MMEF-TEID may include the IP address of the MME_A 40 or may include a TEIDof the MME_A 40.

The eNB/5GBS/WAG Address is an IP address of the eNB_A 45 and/or the5GBS_A 122 and/or the WAG_A 126.

The cNB/5GBS/WAG ID is information for identifying the UE in the eNB_A45 and/or the 5GBS_A 122 and/or the WAG_A 126.

The Radio Bearer Type is information indicating a bearer type. Theinformation indicating the bearer type may be a DRB or a SRB.

Here, the information elements included in the MME context illustratedin FIGS. 12B, 13C and 13D may be included and stored in either a MMcontext 644 or an EPS bearer context.

The Radio Bearer Type is information indicating a bearer type. Theinformation indicating the bearer type may be a DRB or a SRB.

1.2.7. Configuration of SGW

FIG. 14A illustrates an apparatus configuration of the SGW_A 35. Asillustrated in FIG. 14A, the SGW_A 35 comprises a network connectionunit_G 1420, a controller_G 1400, and a storage unit_G 1440. The networkconnection unit_G 1420 and the storage unit_G 1440 are connected to thecontroller_G 1400 via a bus.

The controller_G 1400 is a function unit for controlling the SGW_A 35.The controller_G 1400 implements various processes by reading out andperforming various programs stored in the storage unit_G 1440.

The network connection unit_G 1420 is a function unit through which theSGW_A 35 connects to a base station and/or an access point and/or theMME_A 40 and/or the PGW_A 30 and/or SGSN_A 42 in the access network.Furthermore, the network connection unit_G 1420 is a transmission and/orreception unit through which the SGW_A 35 transmits and/or receives userdata and/or control data to and/or from a base station and/or an accesspoint and/or the MME_A 40 and/or the PGW_A 30 and/or SGSN_A 42 in theaccess network.

The storage unit_G 1440 is a function unit for storing programs, data,and the like necessary for each operation of the SGW_A 35. The storageunit_G 1440 is constituted of, for example, a semiconductor memory, aHard Disk Drive (HDD), or the like.

The storage unit_G 1440 may store at least the identificationinformation and/or the control information and/or the flag and/or theparameter included in the control message transmitted and/or received ina communication procedure that will be described later.

As illustrated in FIG. 14A, the storage unit_G 1440 stores an EPS bearercontext 1442. Note that the EPS bearer context includes an EPS bearercontext stored for each UE, an EPS bearer context stored for each PDUsession, and an EPS bearer context stored for each bearer.

First, FIG. 15B illustrates information elements of the EPS bearercontext stored for each UE. As illustrated in FIG. 15B, the EPS bearercontext stored for each UE includes IMSI, a ME Identity, MSISDN, a MMEF-TEID, a SGW F-TEID, and Network-initiated Session EstablishmentCapability.

The IMSI is permanent identification information of a user. The IMSI isidentical to the IMSI in the HSS_A 50.

The ME Identity is identification information of the UE, and may be theIMEI/IMISV, for example.

The MSISDN represents a basic phone number of the UE. The MSISDN isindicated by the storage unit of the HSS_A 50.

The MME F-TEID is information for identifying the MME_A 40. The MMEF-TEID may include the IP address of the MME_A 40 or may include theTEID of the MME_A 40.

The SGW F-TEID is information for identifying the SGW_A 35. The SGWF-TEID may include the IP address of the SGW_A 35 or may include theTEID of the SGW_A 35.

The Network-initiated Session Establishment Capability is informationindicating whether a network-initiated session establishment procedurecan be performed. The Network-initiated Session Establishment Capabilitymay be further classified into UE Network-initiated SessionEstablishment Capability indicating that the UE_A 10 allows thenetwork-initiated session establishment procedure and NWNetwork-initiated Session Establishment Capability indicating that thecore network_A 90 allows the network-initiated session establishmentprocedure.

Furthermore, the EPS bearer context includes EPS bearer context for eachPDU session stored for each PDU session. FIG. 15C illustrates the EPSbearer context for each PDU session. As illustrated in FIG. 15C, the EPSbearer context for each PDU session includes APN in Use (Data NetworkIdentifier), an Assigned Session Type (Assigned PDN Type), an IPAddress, a SGW F-TEID, a PGW F-TEID, a Default Bearer, and a MobilityType.

The APN in Use (Data Network Identifier) is an APN recently utilized.This APN may include identification information about the network andidentification information about a default operator. Moreover, the APNin Use (Data Network Identifier) may be information for identifying thedata network with which the PDU session is to be established.

The Assigned Session Type (Assigned PDN Type) is information indicatingthe PDU session type. The PDU session type may be of IP type or non-IPtype. Moreover, in a case that the PDU session type is of IP type, theAssigned Session Type may further include information indicating the PDNtype assigned by the network. Note that the PDN type may be of IPv4type, IPv6 type, or IPv4v6 type.

The IP Address is an IP address allocated to the UE. The IP address maybe an IPv4 address, an IPv6 address, or an IPv6 prefix. Note that, in acase that the Assigned Session Type (Assigned PDN Type) indicatesnon-IP, the Assigned Session Type may not necessarily include any IPAddress element.

The SGW F-TEID is information for identifying the SGW_A 35. The SGWF-TEID may include the IP address of the SGW_A 35 or may include theTEID of the SGW_A 35.

The PGW F-TEID is information for identifying the PGW_A 30. The PGWF-TEID may include the IP address of the PGW_A 30 or may include theTEID of the PGW_A 30.

The Default Bearer is information acquired from the core network_A 90 atthe time of establishment of the PDU session and is EPS beareridentification information for identifying a default bearer associatedwith the PDU session.

The Mobility Type is information indicating the granularity of mobility.Further, the Mobility Type may be information indicating the type ofservice continuity.

Furthermore, the EPS bearer context of the SGW includes the EPS bearercontext for each bearer. FIG. 15D illustrates the EPS bearer context foreach bearer. As illustrated in FIG. 15D, the EPS bearer context storedfor each bearer includes an EPS Bearer ID, a TFT, a PGW F-TEID, a SGWF-TEID, a MME/eNB/5GBS/WAG Address, and a MME/eNB/5GBS/WAG ID.

The EPS Bearer ID is the identification information for identifying theEPS bearer for a UE connection via the E-UTRAN.

Note that the EPS Bearer ID may be EPS bearer identification informationfor identifying the dedicated bearer. Hence, the EPS Bearer ID may beidentification information for identifying an EPS bearer different fromthe default bearer.

The TFT is an abbreviation of a “Traffic Flow Template”, and indicatesall packet filters associated with the EPS bearer.

The PGW F-TEID is information for identifying the PGW_A 30. The PGWF-TEID may include the IP address of the PGW_A 30 or may include theTEID of the PGW_A 30.

The SGW F-TEID is information for identifying the SGW_A 35. The SGWF-TEID may include the IP address of the SGW_A 35 or may include theTEID of the SGW_A 35.

The MME/eNB/5GBS/WAG Address is the IP address of the MME_A 40 and/orthe eNB_A 45 and/or the 5GBS_A 122 and/or the WAG_A 126.

The MME/eNB/5GBS/WAG ID is information for identifying the UE in theMME_A 40 and/or the eNB_A 45 and/or the 5GBS_A 122 and/or the WAG_A 126.

1.2.8. Configuration of PGW

FIG. 16A illustrates the apparatus configuration of the PGW_A 30. Asillustrated in FIG. 16A, the PGW_A 30 comprises a network connectionunit_H 1620, a controller_H 1600, and a storage unit_H 1640. The networkconnection unit_H 1620 and the storage unit_H 1640 are connected to thecontroller_H 1600 via a bus.

The controller_H 1600 is a function unit for controlling the PGW_A 30.The controller_H 1600 implements various processes by reading out andperforming various programs stored in the storage unit_H 1640.

The network connection unit_H 1620 is a function unit through which thePGW_A 30 connects to the SGW_A 35 and/or the PCRF_A 60 and/or the ePDG_A65 and/or the AAA_A 55 and/or the TWAG_A 74 and/or the PDN_A 5. Thenetwork connection unit_H 1620 is a transmission and/or reception unitthrough which the PGW_A 30 transmits and/or receives user data and/orcontrol data to and/or from the SGW_A 35 and/or the PCRF_A 60 and/or theePDG_A 65 and/or the AAA_A 55 and/or the TWAG_A 74 and/or the PDN_A 5.

The storage unit_H 1640 is a function unit for storing programs, data,and the like necessary for each operation of the PGW_A 30. The storageunit_H 1640 is constituted of, for example, a semiconductor memory, aHard Disk Drive (HDD), or the like.

The storage unit_H 1640 may store at least the identificationinformation and/or the control information and/or the flag and/or theparameter included in the control message transmitted and/or received ina communication procedure that will be described later.

As illustrated in FIG. 16A, the storage unit_H 1640 stores an EPS bearercontext 1642. Note that the EPS bearer context may be stored in such amanner that an EPS bearer context stored for each UE, an EPS bearercontext stored for each APN, an EPS bearer context stored for each PDUsession, and an EPS bearer context stored for each bearer are separatelystored.

FIG. 17B illustrates information elements included in the EPS bearercontext stored for each UE. As illustrated in FIG. 17B, the EPS bearercontext stored for each UE includes IMSI, anIMSI-unauthenticated-indicator, an ME Identity, MSISDN, a RAT type, andNetwork-initiated Session Establishment Capability.

The EPS bearer context for each UE may include information foridentifying a communication path to be an efficient path.

The IMSI is identification information to be assigned to a user usingthe UE.

The IMSI-unauthenticated-indicator is instruction information indicatingthat this IMSI is not authenticated.

The ME Identity is an ID of the UE, and may be the IMEI/IMISV, forexample.

The MSISDN represents a basic phone number of the UE. The MSISDN isindicated by the storage unit of the HSS_A 50.

The RAT type indicates a recent Radio Access Technology (RAT) of the UE.The RAT type may be, for example, the E-UTRA (LTE), the UTRA, or thelike, or may be 5G RAT or WLAN.

The Network-initiated Session Establishment Capability is informationindicating whether a network-initiated session establishment procedurecan be performed. The Network-initiated Session Establishment Capabilitymay be further classified into UE Network-initiated SessionEstablishment Capability indicating that the UE_A 10 allows thenetwork-initiated session establishment procedure and NWNetwork-initiated Session Establishment Capability indicating that thecore network_A 90 allows the network-initiated session establishmentprocedure.

Next, FIG. 17C illustrates the EPS bearer context stored for each APN.As illustrated in FIG. 17C, the EPS bearer context stored for each APNof the PGW storage unit includes APN in use. Note that the EPS bearercontext stored for each APN may be stored for each Data NetworkIdentifier.

The APN in Use (Data Network Identifier) is an APN recently utilized.This APN may include identification information about the network andidentification information about a default operator. Moreover, the APNin Use (Data Network Identifier) may be information for identifying thedata network with which the PDU session is to be established.

Furthermore, FIG. 17D illustrates the EPS bearer context for each PDUsession stored for each PDU session. As illustrated in FIG. 17D, the EPSbearer context for each PDU session includes an Assigned Session Type(Assigned PDN Type), an IP Address, a SGW F-TEID, a PGW F-TEID, aDefault Bearer, and a Mobility Type.

The Assigned Session Type (Assigned PDN Type) is information indicatingthe PDU session type. The PDU session type may be of IP type or non-IPtype. Moreover, in a case that the PDU session type is of IP type, theAssigned Session Type may further include information indicating the PDNtype assigned by the network. Note that the PDN type may be of IPv4type, IPv6 type, or IPv4v6 type.

The IP Address is an IP address allocated to the UE. The IP address maybe an IPv4 address, an IPv6 address, or an IPv6 prefix. Note that, in acase that the Assigned Session Type (Assigned PDN Type) indicatesnon-IP, the Assigned Session Type may not necessarily include any IPAddress element.

The SGW F-TEID is information for identifying the SGW_A 35. The SGWF-TEID may include the IP address of the SGW_A 35 or may include theTEID of the SGW_A 35.

The PGW F-TEID is information for identifying the PGW_A 30. The PGWF-TEID may include the IP address of the PGW_A 30 or may include theTEID of the PGW_A 30.

The Default Bearer is information acquired from the core network_A 90 atthe time of establishing a PDU session and is EPS bearer identificationinformation for identifying a default bearer associated with the PDUsession.

The Mobility Type is information indicating the granularity of mobility.Further, the Mobility Type may be information indicating the type ofservice continuity.

Furthermore, FIG. 17E illustrates the EPS bearer context stored for eachEPS bearer. As illustrated in FIG. 17E, the EPS context includes an EPSBearer ID, a TFT, a PGW F-TEID, and a SGW F-TEID.

The EPS Bearer ID is the identification information for identifying theEPS bearer for a UE connection via the E-UTRAN.

Note that the EPS Bearer ID may be EPS bearer identification informationfor identifying the dedicated bearer. Hence, the EPS Bearer ID may beidentification information for identifying an EPS bearer different fromthe default bearer.

The TFT is an abbreviation of a “Traffic Flow Template”, and indicatesall packet filters associated with the EPS bearer.

The PGW F-TEID is information for identifying the PGW_A 30. The PGWF-TEID may include the IP address of the PGW_A 30 or may include theTEID of the PGW_A 30.

The SGW F-TEID is information for identifying the SGW_A 35. The SGWF-TEID may include the IP address of the SGW_A 35 or may include theTEID of the SGW_A 35.

1.3. Description of Communication Procedure

Next, a communication procedure according to the present embodiment willbe described with reference to FIG. 18.

Here, before describing the detailed steps of each procedure, in orderto avoid redundant descriptions, terminology specific to the presentembodiment and primary identification information used in each procedurewill be described beforehand.

A single-type PDU session(s) in the present embodiment is one ormultiple PDU sessions supporting first Service continuity. Further,single-type PDU sessions in the present embodiment may be furtherdivided into first, second, and third single types for management.

Here, the first Service continuity is Service continuity ofestablishing, in a state where a first PDU session is established, asecond PDU session, and switching communication for which transmissionand/or reception has been performed in the first PDU session to thesecond PDU session and to thereby continue the communication.Furthermore, in the first Service continuity, the first session may bereleased in a case of switching for the communication. Furthermore, inthe first Service continuity, switching at the time of sessionestablishment and disconnection of communication may be performedaccording to mobility type.

Here, the first PDU session is a first PDU session established firstamong PDU sessions constituting single-type PDU sessions.

Hence, single-type PDU sessions form a session group including such afirst session and a second session. Note that in a transient state wherethe second session is established and the first session is to bereleased, multiple single-type PDU sessions may be established.

A first single-type PDU session(s) in the present embodiment is one ormultiple PDU sessions supporting first Service continuity.

A second single-type PDU session(s) in the present embodiment is one ormultiple PDU sessions supporting first Service continuity. Furthermore,each PDU session of second single-type PDU sessions may be establishedfor a single Data Network (DN).

Furthermore, each PDU session of second single-type PDU sessions may beestablished in association with a single APN and/or a single TFT and/ora single application (application identification information) and/or asingle service (service identification information).

Furthermore, each PDU session of second single-type PDU sessions may beestablished in a single network slice.

A third single-type PDU session(s) in the present embodiment is one ormultiple PDU sessions supporting first Service continuity.

Furthermore, PDU sessions of third single-type PDU sessions may beestablished for different DNs.

Furthermore, PDU sessions of third single-type PDU sessions may beassociated with different APNs.

Furthermore, PDU sessions of third single-type PDU sessions may beestablished in different network slices.

As described above, in the present embodiment, the PDU session groupcapable of performing the first Session continuity may be managed assingle-type PDU sessions. Furthermore, the single-type PDU sessions maybe managed as different single-type PDU sessions according to theabove-described first, second, and third single types. Furthermore, in acase that multiple DNs are configured, multiple first single-type PDUsessions may be managed for each DN. Multiple second single-type PDUsessions may be managed for each APN, TFT, or application. Multiplethird single-type PDN sessions may be managed for each network slice.

A multi-type PDU session(s) in the present embodiment is one or multiplePDU sessions supporting second Service continuity. Multi-type PDUsessions in the present embodiment may be further divided into first,second, and third multi-types for management.

Here, the second Service continuity is Service continuity ofestablishing, in a state where a first PDU session is established, asecond PDU session, and switching communication for which transmissionand/or reception has been performed in the first PDU session to thesecond PDU session and thereby continuing the communication.Furthermore, in the second Service continuity, the first session may bereleased in a case of switching for the communication. The secondService continuity is Service continuity in which, in a state wheremultiple PDU sessions are established, switching between the sessions isperformed for communication to thereby continue the communication. Notethat, in the second Service continuity, the first PDU session, which isthe source of the switching, may be maintained in a case of switchingfor the communication.

In other words, in the second Service continuity, communicationperformed in a certain PDU session can be switched from the certain PDUsession to another PDU session in a state where multiple PDU sessionsare established. Note that, in the second Service continuity, switchingat the time of establishing a session and disconnection of communicationmay be performed according to mobility type.

Here, the first PDU session is a first PDU session established firstamong PDU sessions constituting single-type PDU sessions. Moreover, themulti-type PDU sessions may include three or more PDU sessions insteadof being limited to the first and second PDU sessions.

Note that, in the present embodiment, identification information foridentifying each of single-type PDU sessions and information foridentifying each of PDU sessions constituting the single-type PDUsessions may be managed separately. The identification information foridentifying single-type PDU sessions and information for identifyingfirst PDU session constituting the single-type PDU sessions may bemanaged using the same identification information, or the identificationinformation of the second PDU session may be used as identificationinformation of the single-type PDU sessions in a case of release of thefirst PDU session. Furthermore, in a case of release of the first PDUsession, identification information for identifying the first PDUsession may be used as the identification information of the second PDUsession.

A first multi-type PDU session(s) in the present embodiment is one ormultiple PDU sessions supporting second Service continuity.

A second multi-type PDU session(s) in the present embodiment is one ormultiple PDU sessions supporting second Service continuity.

Furthermore, each PDU session of second multi-type PDU sessions may beestablished for a single Data Network (DN).

Furthermore, each PDU session of second multi-type PDU sessions may beassociated with a single APN and/or a single TFT and/or a singleapplication (application identification information) and/or a singleservice (service identification information).

Furthermore, each PDU session of second multi-type PDU sessions may beestablished in a single network slice.

A third multi-type PDU session(s) in the present embodiment is one ormultiple PDU sessions supporting second Service continuity.

Furthermore, PDU sessions of third multi-type PDU sessions may beestablished for different DNs.

Furthermore, PDU sessions of third multi-type PDU sessions may beestablished in association with different APNs.

Furthermore, PDU sessions of third multi-type PDU sessions may beestablished in different network slices.

As described above, in the present embodiment, the PDU session groupcapable of performing the second Session continuity may be managed asmulti-type PDU sessions. Furthermore, the multi-type PDU sessions may bemanaged as different multi-type PDU sessions according to theabove-described first, second, and third types. Furthermore, in a casethat multiple DNs are configured, multiple first multi-type PDU sessionsmay be managed for each DN. Multiple second multi-type PDU sessions maybe managed for each APN, TFT, or application. Multiple third multi-typePDN sessions may be managed for each network slice.

Note that, in the present embodiment, identification information foridentifying each of multi-type PDU sessions and information foridentifying each of PDU sessions constituting the single-type PDUsessions may be managed separately. Identification information foridentifying the multi-type PDU sessions and identification informationfor identifying the first PDU session constituting the multi-type PDUsession may be managed using the same identification information.

A first state, a second state, and a third state in the presentembodiment will be described with reference to FIG. 4. In the example inFIG. 4, the first PDU session is a PDU session established between theUE_A 10 and the PGW_A 30. More specifically, the first PDU session maybe a PDU session established between the UE_A 10 and the PGW_A 30 viathe access network and the SGW_A 35. Moreover, the first PDU session maybe a PDU session established between the UE_A 10 and the PGW_A 30 viathe access network, the MME_A 40, and the SGW_A 35.

The second PDU session is a PDU session established between the UE_A 10and the SCEF_A 46. More specifically, the second PDU session may be aPDU session established between the UE_A 10 and the SCEF_A 46 via theaccess network and the MME_A 40.

The first state in the present embodiment is a state where the UE_A 10is registered in the core network_A 90. In the first state, the UE_A 10and/or the MME_A 40 and/or the SGW_A 35 and/or the PGW_A 30 and/or theSCEF_A 46 may, or may not necessarily, have established a PDU session.Note that the first state may be a state where a PDU session has notbeen established.

The second state in the present embodiment is a state where the UE_A 10and the core network_A 90 have established the first PDU session. Here,the first session may be established in the attach procedure. In thiscase, the state for making the attach procedure completed may be thesecond state, instead of the first state.

The third state in the present embodiment is a state where the UE_A 10and the core network_A 90 have established a second PDU session and alsoa state where the first or the second Service continuity is completed.

Note that the first or second Service continuity may be performed basedon the establishment of the second PDU session or may be performed atany timing after the establishment of the second session.

Furthermore, release of the first PDU session may be performed based onperforming of the first or second Service continuity or may be performedat any timing after the first or second Service continuity is performed.

Here, in the example in FIG. 4, a description has been given by assumingthat the first PDU session is a PDU session established between the UE_A10 and the PGW_A 30 and that the second PDU session is a PDU sessionestablished between the UE_A 10 and the SCEF_A 46.

However, the first PDU session and the second PDU session need not belimited to this. The first PDU session may be a PDU session establishedbetween the UE_A 10 and the SCEF_A 46, and the second PDU session may bea PDU session established between the UE_A 10 and the PGW_A 30.

Alternatively, the first PDU session may be a PDU session establishedbetween the UE_A 10 and the SCEF_A 46, and the second PDU session may bea PDU session established by the UE_A 10 with a SCEF different from theSCEF_A 46.

Alternatively, the first PDU session may be a PDU session establishedbetween the UE_A 10 and the PGW_A 30, and the second PDU session may bea PDU session established by the UE_A 10 with a PGW different from thePGW_A 30.

As described above, the UE_A 10 can continue a service by switching, forcommunication, between PDU sessions established with different gateways,such as the PGW_A 30 and the SCEF_A 46, connecting between the corenetwork_A 90 and the DN.

This allows, for example, that, in a case of moving of the UE_A 10 thathas established a PDU session with a certain gateway device, the UE_A 10can switch, for the communication, from the PDU session to a PDU sessionestablished with another gateway device that is located geologicallyclose to the UE_A 10. Hence, the Service continuity described in thepresent embodiment can perform optimization of delivery traffic, optimalcommunication path selection, and the like.

First identification information in the present embodiment isinformation indicating an access network to which the UE_A 10 isconnectable. Furthermore, the first identification information may beinformation indicating the priority level of an access network to whichthe UE_A 10 is connectable.

Note that the access network in the present embodiment may be a 3GPPaccess network or may be a non-3GPP access network. Furthermore, the3GPP access network may be an E-UTRAN, an access network for the LTE, oran access network for 5G. Furthermore, the non-3GPP access network maybe a WLAN access network.

Second identification information in the present embodiment isinformation indicating an access network to which the network isconnectable. Furthermore, the second identification information may beinformation indicating the priority level of an access network to whichthe network is connectable.

Third identification information in the present embodiment isinformation indicating that a network-initiated session establishmentprocedure is allowed.

Fourth identification information in the present embodiment isinformation (NW capability) indicating that the network is capable of anetwork-initiated session establishment procedure. Furthermore, thefourth identification information may be capability information of thecore network_A 90 indicating that network-initiated sessionestablishment can be performed. Furthermore, the fourth identificationinformation may be information indicating that a network-initiatedsession establishment procedure is allowed to be performed afterreception of identification information.

Fifth identification information in the present embodiment isinformation (UE capability) indicating that the UE_A 10 is capable ofperforming a network-initiated session establishment procedure.Furthermore, the fourth identification information may be capabilityinformation of the UE_A 10 indicating that network-initiated sessionestablishment can be performed. Furthermore, the fifth identificationinformation may be information indicating that a network-initiatedsession establishment procedure is allowed to be performed afterreception of identification information.

Sixth identification information in the present embodiment isinformation indicating a requested session type. The sixthidentification information may indicate IP or non-IP.

Seventh identification information in the present embodiment may beinformation indicating the IP Address of the UE_A 10. Note that the IPaddress may be an IPv4 address, an IPv6 address, or an IPv6 prefix.Furthermore, the seventh identification information may be informationindicating a requested type of IP address of the UE_A 10. Note thatallocation of the IP address of the UE_A 10 may be performed by thePGW_A 30 or may be performed by the MME_A 40.

Eighth identification information in the present embodiment isinformation indicating whether or not to establish a Data Radio Bearer(DRB), which is a radio bearer for transmitting and/or receiving userdata. Furthermore, the eighth identification information may beinformation indicating a requested type of radio bearer to be used fortransmission and/or reception of user data. Note that the type of theradio bearer to be used for transmission and/or reception of user datamay be a Data Radio Bearer (DRB) or a Signalling Radio Bearer (SRB).Furthermore, the eighth identification information may include requestedinformation related to transmission and/or reception of user data. Forexample, the eighth identification information may include a requestedTFT.

Ninth identification information in the present embodiment isinformation for identifying data network that is a destination ofestablishment of a requested PDU session. The information foridentifying a data network may be an Access Point Name (APN). The ninthidentification information may be application identification informationfor identifying an application or service identification information foridentifying a service, associated with a PDU session requested to beestablished.

Tenth identification information in the present embodiment isinformation indicating a requested mobility type.

The eleventh identification information in the present embodiment isinformation indicating an allowed session type. The eleventhidentification information may indicate IP or non-IP.

Twelfth identification information in the present embodiment may beinformation indicating the IP address of the UE_A 10. Note that the IPaddress may be an IPv4 address, an IPv6 address, or an IPv6 prefix.Furthermore, the twelfth identification information may be informationindicating an allowed type of IP address of the UE_A 10. Note thatallocation of the IP address of the UE_A 10 may be performed by thePGW_A 30 or may be performed by the MME_A 40.

Thirteenth identification information in the present embodiment isinformation indicating whether or not a Data Radio Bearer (DRB), whichis a radio bearer for transmitting and/or receiving user data isestablished. Furthermore, the thirteenth identification information maybe information indicating an allowed type of radio bearer to be used fortransmission and/or reception of user data. Note that the type of theradio bearer to be used for transmission and/or reception of user datamay be a Data Radio Bearer (DRB) or a Signalling Radio Bearer (SRB).Furthermore, the thirteenth identification information may includeallowed information related to transmission and/or reception of userdata. For example, the thirteenth identification information may includean allowed TFT.

Fourteenth identification information in the present embodiment isinformation for identifying a data network that is the destination ofestablishment of an allowed PDU session. Note that the information foridentifying a data network may be an Access Point Name (APN). Thefourteenth identification information may be application identificationinformation for identifying an application or service identificationinformation for identifying a service, associated with a PDU sessionallowed to be established.

Fifteenth identification information in the present embodiment isinformation indicating an allowed mobility type.

Sixteenth identification information in the present embodiment iscapability information of a UE (UE capability) indicating that a sessionsupporting Service Continuity can be established. Furthermore, thesixteenth identification information may be capability information of aUE (UE capability) indicating that a session with which communicationcan be continued by switching, for the communication, the session to adifferent session can be established. Furthermore, the sixteenthidentification information may be information for allowing that servicecontinuity can be performed after reception of identificationinformation.

Seventeenth identification information in the present embodiment iscapability information of a network (NW capability) indicating that asession supporting Service Continuity can be established. Furthermore,the seventeenth identification information may be capability informationof a network (NW capability) indicating that a session with whichcommunication can be continued by switching, for the communication, thesession to a different session can be established. Furthermore, theseventeenth identification information may be information for allowingthat service continuity can be performed after reception ofidentification information.

Eighteenth identification information in the present embodiment iscapability information of a UE (UE capability) indicating that ServiceContinuity is supported between sessions established for a single DataNetwork (DN). Furthermore, the eighteenth identification information maybe capability information of a UE (UE capability) indicating that asession with which communication can be continued by switching, for thecommunication, the session to a different session established for asingle DN can be established.

The eighteenth identification information may be capability informationof a UE (UE capability) indicating that Service Continuity is supportedbetween sessions associated with a single APN and/or a TFT and/or anapplication (application identification information) and/or a service(service identification information). The eighteenth identificationinformation may be capability information of a UE (UE capability)indicating that a session with which communication can be continued byswitching, for the communication, the session to a different sessionassociated with a single APN and/or a TFT and/or an application(application identification information) and/or a service (serviceidentification information) can be established.

The eighteenth identification information may be capability informationof a UE (UE capability) indicating that Service Continuity is supportedbetween sessions established in a single network slice. Furthermore, theeighteenth identification information may be capability information of aUE (UE capability) indicating that a session with which communicationcan be continued by switching the session to a different sessionestablished in the same network slice can be established.

Nineteenth identification information in the present embodiment iscapability information of a network (NW capability) indicating thatService Continuity is supported between sessions established for asingle DN. Furthermore, the nineteenth identification information may becapability information of a network (NW capability) indicating that asession with which communication can be continued by switching, for thecommunication, the session to a different session established for asingle DN can be established.

The nineteenth identification information may be capability informationof a network (NW capability) indicating that Service Continuity issupported between sessions associated with a single APN and/or a TFTand/or an application (application identification information) and/or aservice (service identification information). The nineteenthidentification information may be capability information of a network(NW capability) indicating that a session with which communication canbe continued by switching, for the communication, the session to adifferent session associated with a single APN and/or a TFT and/or anapplication (application identification information) and/or a service(service identification information) can be established.

The nineteenth identification information may be capability informationof a U network (NW capability) indicating that Service Continuity issupported between sessions established in a single network slice.Furthermore, the nineteenth identification information may be capabilityinformation of a network (NW capability) indicating that a session withwhich communication can be continued by switching, for communication,the session to a different session established in the same network slicecan be established.

Twentieth identification information in the present embodiment iscapability information of a UE (UE capability) indicating that ServiceContinuity is supported between sessions established for different DNs.The twentieth identification information may be capability informationof a UE (UE capability) indicating that Service Continuity is supportedbetween sessions associated with different APNs.

Furthermore, the twentieth identification information may be capabilityinformation of a UE (UE capability) indicating that a session with whichcommunication can be continued by switching, for the communication, thesession to a different session established with a different DN can beestablished. Furthermore, the twentieth identification information maybe capability information of a UE (UE capability) indicating that asession with which communication can be continued by switching, for thecommunication, the session to a different session associated with adifferent APN can be established.

The twentieth identification information may be capability informationof a UE (UE capability) indicating that Service Continuity is supportedbetween sessions established in different network slices. Furthermore,the twentieth identification information may be capability informationof a UE (UE capability) indicating that a session with whichcommunication can be continued by switching, for the communication, thesession to a different session established in a different network slicecan be established. Twenty-first identification information in thepresent embodiment is capability information of a network (NWcapability) indicating that Service Continuity between differentsessions established in different DNs is supported. Furthermore, thetwenty-first identification information may be capability information ofa network (NW capability) indicating that Service Continuity issupported between sessions associated with different APNs.

Furthermore, the twenty-first identification information may becapability information of a network (NW capability) indicating that asession with which communication can be continued by switching, for thecommunication, the session to a different session established with adifferent DN can be established. Furthermore, the twenty-firstidentification information may be capability information of a network(NW capability) indicating that a session with which communication canbe continued by switching, for the communication, the session to adifferent session associated with a different APN can be established.

The twenty-first identification information may be capabilityinformation of a network (NW capability) indicating that ServiceContinuity is supported between sessions established in differentnetwork slices. Furthermore, the twenty-first identification informationmay be capability information of a network (NW capability) indicatingthat a session with which communication can be continued by switchingthe session to a different session established in a different networkslice can be established.

Twenty-second identification information in the present embodiment iscapability information of a UE (UE capability) indicating that multiplesessions supporting Service Continuity can be established. Furthermore,the twenty-second identification information may be capabilityinformation of a UE (UE capability) indicating that multiple sessionswith which communication can be continued by switching, for thecommunication, any of the sessions to a different session can beestablished. Furthermore, the twenty-second identification informationmay be information for allowing that service continuity can be performedafter reception of identification information.

Twenty-third identification information in the present embodiment iscapability information of a network (NW capability) indicating thatmultiple sessions supporting Service Continuity can be established.Furthermore, the twenty-third identification information may becapability information of a network (NW capability) indicating thatmultiple sessions with which communication can be continued byswitching, for the communication, any of the sessions to a differentsession can be established. Furthermore, the twenty-third identificationinformation may be information for allowing that service continuity canbe performed after reception of identification information.

Twenty-fourth identification information in the present embodiment iscapability information of a UE (UE capability) indicating that multiplesessions supporting Service Continuity between sessions established fora single DN can be established. Furthermore, the twenty-fourthidentification information may be capability information of a UE (UEcapability) indicating that multiple sessions with which communicationcan be continued by switching, for the communication, any of thesessions to a different session established for a single DN can beestablished.

Furthermore, the twenty-fourth identification information may becapability information of a UE (UE capability) indicating that multiplesessions that are associated with a single APN and/or a TFT and/or anapplication (application identification information) and/or a service(service identification information) and that can be switched betweeneach other for communication can be established. Furthermore, thetwenty-fourth identification information may be capability informationof a UE (UE capability) indicating that multiple sessions that areassociated with a single APN and/or a TFT and/or an application(application identification information) and/or a service (serviceidentification information) and that can be switched between each otherfor communication can be established.

The twenty-fourth identification information may be capabilityinformation of a UE (UE capability) indicating that multiple sessionscapable of Service Continuity between sessions established in a singlenetwork slice can be established. Furthermore, the twenty-fourthidentification information may be capability information of a UE (UEcapability) indicating that multiple sessions with which communicationcan be continued by switching among the sessions established in the samenetwork slice for communication can be established.

Twenty-fifth identification information in the present embodiment iscapability information of a network (NW capability) indicating thatmultiple sessions supporting Service Continuity between sessionsestablished for a single DN can be established. Furthermore, thetwenty-fifth identification information may be capability information ofa network (NW capability) indicating that multiple sessions with whichcommunication can be continued by switching, for the communication, anyof the sessions to a different session established for a single DN canbe established.

Furthermore, the twenty-fifth identification information may becapability information of a network (NW capability) indicating thatmultiple sessions that are associated with a single APN and/or a TFTand/or an application (application identification information) and/or aservice (service identification information) and that can be switchedbetween each other for communication can be established. Furthermore,the twenty-fifth identification information may be capabilityinformation of a network (NW capability) indicating that multiplesessions that are associated with a single APN and/or a TFT and/or anapplication (application identification information) and/or a service(service identification information) and that can be switched betweeneach other for communication can be established.

The twenty-fifth identification information may be capabilityinformation of a network (NW capability) indicating that multiplesessions capable of Service Continuity between sessions established in asingle network slice can be established. Furthermore, the twenty-fifthidentification information may be capability information of a network(NW capability) indicating that multiple sessions with whichcommunication can be continued by switching among the sessionsestablished in the same network slice for communication can beestablished.

Twenty-sixth identification information in the present embodiment iscapability information of a UE (UE capability) indicating that multiplesessions supporting Service Continuity between sessions established fordifferent DNs can be established. The twenty-sixth identificationinformation may be capability information of a UE (UE capability)indicating that multiple sessions supporting Service Continuity betweensessions associated with different APNs can be established.

Furthermore, the twenty-sixth identification information may becapability information of a UE (UE capability) indicating that multiplesessions with which communication can be continued by switching, for thecommunication, any of the sessions to a different session establishedwith a different DN can be established. Furthermore, the twenty-sixthidentification information may be capability information of a UE (UEcapability) indicating that multiple sessions with which communicationcan be continued by switching, for the communication, any of thesessions to a different session associated with a different APN can beestablished.

The twenty-sixth identification information may be capabilityinformation of a UE (UE capability) indicating that multiple sessionssupporting Service Continuity between sessions established in adifferent network slice can be established. Furthermore, thetwenty-sixth identification information may be capability information ofa UE (UE capability) indicating that multiple session with whichcommunication can be continued by switching, for communication, any ofthe sessions to a different session established in the different networkslice can be established.

Twenty-seventh identification information in the present embodiment iscapability information of a network (NW capability) indicating thatmultiple sessions supporting Service Continuity between sessionsestablished for different DNs can be established. Furthermore, thetwenty-seventh identification information may be capability informationof a network (NW capability) indicating that multiple sessionssupporting Service Continuity between sessions associated with differentAPNs can be established.

Furthermore, the twenty-seventh identification information may becapability information of a network (NW capability) indicating thatmultiple sessions with which communication can be continued byswitching, for the communication, any of the sessions to a differentsession established with a different DN can be established. Furthermore,the twenty-seventh identification information may be capabilityinformation of a UE (capability information of a network (NWcapability)) indicating that multiple sessions with which communicationcan be continued by switching, for the communication, any of thesessions to a different session associated with a different APN can beestablished.

The twenty-seventh identification information may be capabilityinformation of a network (NW capability) indicating that multiplesessions supporting Service Continuity between sessions established in adifferent network slice can be established. Furthermore, thetwenty-seventh identification information may be capability informationof a network (NW capability) indicating that multiple sessions withwhich communication can be continued by switching, for communication,any of the sessions to a different session established in a differentnetwork slice can be established.

Twenty-eighth identification information in the present embodiment isinformation indicating that establishment of an Initial Sessioncorresponding to the first and/or second and/or third single-type PDUsession is requested. Furthermore, the twenty-eighth identificationinformation may be information indicating a first and/or second and/orthird single-type PDU session.

Twenty-ninth identification information in the present embodiment may beinformation indicating that establishment of an Initial Sessioncorresponding to the first and/or second and/or third single-type PDUsession is allowed. The twenty-ninth identification information may beinformation for identifying the first and/or second and/or thirdsingle-type PDU session allowed to be established.

Furthermore, the twenty-ninth identification information may beinformation indicating that the session to be established is the firstand/or second and/or third single-type PDU session. Furthermore, thetwenty-ninth identification information may be information indicatingthat the session to be established is an Initial Session correspondingto the first and/or second and/or third single-type PDU session.Furthermore, the twenty-ninth identification information may beinformation for identifying a session allowed to be established. Inaddition, the twenty-ninth identification information may includeinformation for identifying single-type PDU sessions including a PDUsession to be established.

Thirtieth identification information in the present embodiment isinformation indicating that establishment of an Additional Sessioncorresponding to the first and/or second and/or third single-type PDUsession is requested. Furthermore, the thirtieth identificationinformation may be information indicating the first and/or second and/orthird single-type PDU session. Furthermore, the thirtieth identificationinformation may be information for identifying another session includedin the single-type sessions. In other words, the thirtiethidentification information may be information for identifying a PDUsession established in the first PDU session establishment procedureand/or a PDU session currently used for communication. Furthermore, thethirtieth identification information may be information indicating thatthe PDU session established in the first PDU session establishmentprocedure and/or the PDU session currently used for communication is tobe released. In addition, the thirtieth identification information mayinclude information for identifying a single-type PDU session includinga PDU session to be established or released.

Thirty-first identification information in the present embodiment may beinformation indicating that establishment of an Additional Sessioncorresponding to the first and/or second and/or third single-type PDUsession is allowed. Furthermore, the thirty-first identificationinformation may be information for identifying the first and/or secondand/or third single-type PDU session allowed to be established.

Furthermore, the thirty-first identification information may beinformation indicating that the session to be established is the firstand/or second and/or third single-type PDU session. Furthermore, thethirty-first identification information may be information indicatingthat the session to be established is an Additional Sessioncorresponding to the first and/or second and/or third single-type PDUsession.

Furthermore, the thirty-first identification information may beinformation for identifying a session allowed to be established.Furthermore, the thirty-first identification information may beinformation for identifying another session included in the single-typesessions. In other words, the thirty-first identification informationmay be information for identifying a PDU session established in thefirst PDU session establishment procedure and/or a PDU session currentlyused for communication. In addition, the thirty-first identificationinformation may include information for identifying single-type PDUsessions including a PDU session to be established.

Furthermore, the thirty-first identification information may beinformation indicating that sessions have been switched and/or servicecontinuity in a single-type PDU session has been performed. Furthermore,the thirty-first identification information may be information foridentifying another session included in single-type sessions (such asthe Initial Session or the session currently used for communication).Furthermore, the thirty-first identification information may beinformation for indicating release of another session included in thesingle-type sessions. In other words, the thirty-first identificationinformation may be information indicating that a PDU session establishedin the first PDU session establishment procedure and/or a PDU sessioncurrently used for communication is released. In addition, thethirty-first identification information may include information foridentifying a single-type PDU session including a PDU session to beestablished or released.

Thirty-second identification information in the present embodiment isinformation indicating that establishment of an Initial Sessioncorresponding to the first and/or second and/or third single-type PDUsession is requested. Furthermore, the thirty-second identificationinformation may be information indicating the first and/or second and/orthird single-type PDU session.

Thirty-third identification information in the present embodiment isinformation indicating that establishment of an Initial Sessioncorresponding to the first and/or second and/or third single-type PDUsession is allowed. Furthermore, the thirty-third identificationinformation may be information for identifying the first and/or secondand/or third single-type PDU session allowed to be established.

Furthermore, the thirty-third identification information may beinformation indicating that the session to be established is the firstand/or second and/or third single-type PDU session. Furthermore, thethirty-third identification information may be information indicatingthat the session to be established is an Initial Session correspondingto the first and/or second and/or third single-type PDU session.Furthermore, the thirty-third identification information may beinformation for identifying a session allowed to be established. Inaddition, the thirty-third identification information may includeinformation for identifying single-type PDU sessions including a PDUsession to be established.

Thirty-fourth identification information in the present embodiment isinformation indicating that establishment of an Additional Sessioncorresponding to the first and/or second and/or third single-type PDUsession is requested. Furthermore, the thirty-fourth identificationinformation may be information indicating the first and/or second and/orthird single-type PDU session. Furthermore, the thirty-fourthidentification information may be information for identifying anothersession included in the single-type sessions. In other words, thethirty-fourth identification information may be information foridentifying a PDU session established in the first PDU sessionestablishment procedure and/or a PDU session currently used forcommunication. Furthermore, the thirty-fourth identification informationmay be information indicating that the PDU session established in thefirst PDU session establishment procedure and/or the PDU sessioncurrently used for communication is to be released. In addition, thethirty-fourth identification information may include information foridentifying a single-type PDU session including a PDU session to beestablished or released.

Thirty-fifth identification information in the present embodiment isinformation indicating that establishment of an Additional Sessioncorresponding to the first and/or second and/or third single-type PDUsession is allowed. Furthermore, the thirty-fifth identificationinformation may be information for identifying the first and/or secondand/or third single-type PDU session allowed to be established.

Furthermore, the thirty-fifth identification information may beinformation indicating that the session to be established is the firstand/or second and/or third single-type PDU session. Furthermore, thethirty-fifth identification information may be information indicatingthat the session to be established is an Additional Sessioncorresponding to the first and/or second and/or third single-type PDUsession.

Furthermore, the thirty-fifth identification information may beinformation for identifying a session allowed to be established.Furthermore, the thirty-fifth identification information may beinformation for identifying another session included in single-typesessions (such as the Initial Session or the session currently used forcommunication).

Furthermore, the thirty-fifth identification information may beinformation indicating that sessions have been switched and/or servicecontinuity in a single-type PDU session has been performed.

Furthermore, the thirty-fifth identification information may beinformation for identifying another session included in the single-typesessions. In other words, the thirty-fifth identification informationmay be information for identifying a PDU session established in thefirst PDU session establishment procedure and/or a PDU session currentlyused for communication.

Furthermore, the thirty-fifth identification information may beinformation for indicating release of another session included in thesingle-type sessions. In other words, the thirty-fifth identificationinformation may be information indicating that a PDU session establishedin the first PDU session establishment procedure and/or a PDU sessioncurrently used for communication is released. In addition, thethirty-fifth identification information may include information foridentifying a single-type PDU session including a PDU session to beestablished or released.

Thirty-sixth identification information in the present embodiment isinformation indicating that establishment of an Initial Sessioncorresponding to a first and/or second and/or third multi-type PDUsession is requested. Furthermore, the thirty-sixth identificationinformation may be information indicating a first and/or second and/orthird multi-type PDU session.

Thirty-seventh identification information in the present embodiment isinformation indicating that establishment of an Initial Sessioncorresponding to the first and/or second and/or third multi-type PDUsession is allowed. Furthermore, the thirty-seventh identificationinformation may be information for identifying the first and/or secondand/or third multi-type PDU session allowed to be established.

Furthermore, the thirty-seventh identification information may beinformation indicating that the session to be established is the firstand/or second and/or third multi-type PDU session. Furthermore, thethirty-seventh identification information may be information indicatingthat the session to be established is an Initial Session correspondingto the first and/or second and/or third multi-type PDU session.Furthermore, the thirty-seventh identification information may beinformation for identifying a session allowed to be established. Inaddition, the thirty-seventh identification information may includeinformation for identifying multi-type PDU sessions including a PDUsession to be established.

Thirty-eighth identification information in the present embodiment maybe information indicating that establishment of an Additional Sessioncorresponding to the first and/or second and/or third multi-type PDUsession is requested. Furthermore, the thirty-eighth identificationinformation may be information indicating the first and/or second and/orthird multi-type PDU session. Furthermore, the thirty-eighthidentification information may be information for identifying anothersession included in multi-type sessions. In other words, thethirty-eighth identification information may be information foridentifying a PDU session established in the first PDU sessionestablishment procedure and/or a PDU session currently used forcommunication. Furthermore, the thirty-eighth identification informationmay be information indicating that the PDU session established in thefirst PDU session establishment procedure and/or the PDU sessioncurrently used for communication is maintained without being released.

Thirty-ninth identification information in the present embodiment may beinformation indicating that establishment of an Additional Sessioncorresponding to the first and/or second and/or third multi-type PDUsession is allowed. Furthermore, the thirty-ninth identificationinformation may be information for identifying the first and/or secondand/or third multi-type PDU session allowed to be established.

Furthermore, the thirty-ninth identification information may beinformation indicating that the session to be established is the firstand/or second and/or third multi-type PDU session. Furthermore, thethirty-ninth identification information may be information indicatingthat the session to be established is an Additional Sessioncorresponding to the first and/or second and/or third multi-type PDUsession.

Furthermore, the thirty-ninth identification information may beinformation for identifying a session allowed to be established.Furthermore, the thirty-ninth identification information may beinformation for identifying another session included in multi-typesessions. In other words, the thirty-ninth identification informationmay be information for identifying a PDU session established in thefirst PDU session establishment procedure and/or a PDU session currentlyused for communication.

Furthermore, the thirty-ninth identification information may beinformation indicating that sessions have been switched and/or servicecontinuity in a multi-type PDU session has been performed. Furthermore,the thirty-ninth identification information may be informationindicating that the PDU session established in the first PDU sessionestablishment procedure and/or the PDU session currently used forcommunication is maintained without being released.

Fortieth identification information in the present embodiment isinformation indicating that establishment of an Initial Sessioncorresponding to the first and/or second and/or third multi-type PDUsession is requested. Furthermore, the forty-first identificationinformation may be information indicating the first and/or second and/orthird multi-type PDU session.

Forty-first identification information in the present embodiment isinformation indicating that establishment of an Initial Sessioncorresponding to the first and/or second and/or third multi-type PDUsession is allowed. Furthermore, the forty-first identificationinformation may be information for identifying the first and/or secondand/or third multi-type PDU session allowed to be established.

Furthermore, the forty-first identification information may beinformation indicating that the session to be established is the firstand/or second and/or third multi-type PDU session. Furthermore, theforty-first identification information may be information indicatingthat the session to be established is an Initial Session correspondingto the first and/or second and/or third multi-type PDU session.Furthermore, the forty-first identification information may beinformation for identifying a session allowed to be established.

Forty-second identification information in the present embodiment may beinformation indicating that establishment of an Additional Sessioncorresponding to the first and/or second and/or third multi-type PDUsession is requested. Furthermore, the forty-second identificationinformation may be information indicating the first and/or second and/orthird multi-type PDU session. Furthermore, the forty-secondidentification information may be information for identifying anothersession included in multi-type sessions. In other words, theforty-second identification information may be information foridentifying a PDU session established in the first PDU sessionestablishment procedure and/or a PDU session currently used forcommunication. Furthermore, the forty-second identification informationmay be information indicating that the PDU session established in thefirst PDU session establishment procedure and/or the PDU sessioncurrently used for communication is maintained without being released.

Forty-third identification information in the present embodiment may beinformation indicating that establishment of an Additional Sessioncorresponding to the first and/or second and/or third multi-type PDUsession is allowed. Furthermore, the forty-third identificationinformation may be information for identifying the first and/or secondand/or third multi-type PDU session allowed to be established.

Furthermore, the forty-third identification information may beinformation indicating that the session to be established is the firstand/or second and/or third multi-type PDU session. Furthermore, theforty-third identification information may be information indicatingthat the session to be established is an Additional Sessioncorresponding to the first and/or second and/or third multi-type PDUsession.

Furthermore, the forty-third identification information may beinformation for identifying a session allowed to be established.Furthermore, the forty-third identification information may beinformation for identifying another session included in multi-typesessions. In other words, the forty-third identification information maybe information for identifying a PDU session established in the firstPDU session establishment procedure and/or a PDU session currently usedfor communication.

Furthermore, the forty-third identification information may beinformation indicating that sessions have been switched and/or servicecontinuity in a multi-type PDU session has been performed. Furthermore,the forty-third identification information may be information indicatingthat the PDU session established in the first PDU session establishmentprocedure and/or the PDU session currently used for communication ismaintained without being released.

Forty-fourth identification information in the present embodiment isinformation indicating that switching of a session is requested.Furthermore, the forty-fourth identification information may beinformation for identifying a multi-type session currently used forcommunication. Furthermore, the forty-fourth identification informationmay be information for identifying a multi-type session to be aswitching destination.

Furthermore, the forty-fourth identification information may beinformation indicating that a switching source PDU session is maintainedwithout being released.

Forty-fifth identification information in the present embodiment isinformation indicating that switching of a session is allowed.Furthermore, the forty-fifth identification information may beinformation for identifying a first and/or second and/or thirdmulti-type PDU session allowed to be switched.

Furthermore, the forty-fifth identification information may beinformation indicating that the session to be switched is the firstand/or second and/or third multi-type PDU session. Furthermore, theforty-fifth identification information may be information foridentifying a session allowed to be switched.

Furthermore, the forty-fifth identification information may beinformation for identifying a switching destination session.Furthermore, the forty-fifth identification information may beinformation for identifying a switching source session. Furthermore, theforty-fifth identification information may be information indicatingthat sessions have been switched and/or service continuity in amulti-type PDU session has been performed.

Furthermore, the forty-fifth identification information may beinformation indicating that a switching source PDU session is maintainedwithout being released.

Forty-sixth identification information in the present embodiment isinformation indicating that switching of a session is requested.Furthermore, the forty-sixth identification information may beinformation for identifying a multi-type session currently used incommunication. Furthermore, the forty-sixth identification informationmay be information for identifying a multi-type session to be aswitching destination.

Furthermore, the forty-sixth identification information may beinformation indicating that a switching source PDU session is maintainedwithout being released.

Forty-seventh identification information in the present embodiment isinformation indicating that switching of a session is allowed.Furthermore, the forty-seventh identification information may beinformation for identifying the first and/or second and/or thirdmulti-type PDU session allowed to be switched.

Furthermore, the forty-seventh identification information may beinformation indicating that the session to be switched is the firstand/or second and/or third multi-type PDU session. Furthermore, theforty-seventh identification information may be information foridentifying a session allowed to be switched. Furthermore, theforty-seventh identification information may be information foridentifying a switching destination session.

Furthermore, the forty-seventh identification information may beinformation for identifying a switching source session. Furthermore, theforty-seventh identification information may be information indicatingthat sessions have been switched and/or service continuity in amulti-type PDU session has been performed.

Furthermore, the forty-seventh identification information may beinformation indicating that a switching source PDU session is maintainedwithout being released.

As illustrated in FIG. 18, in the communication procedure in the presentembodiment, an attach procedure (S1800) is performed first. Through theattach procedure, the UE_A 10 connects to the core network_A 90. TheUE_A 10 and/or the MME_A 40 and/or SGW_A 35 and/or PGW_A 30 and/or theSCEF_A 46 may exchange various kinds of capability information of theUE_A 10 and/or the core network_A 90 in the attach procedure.Specifically, information indicating capability of supportingnetwork-initiated session establishment and/or information indicatingcapability of supported Service Continuity may be exchanged.

Details of the attach procedure will be described later.

In a case of completion of the attach procedure, the UE_A 10 and/or theMME_A 40 and/or the SGW_A 35 and/or the PGW_A 30 and/or the SCEF_A 46change to the first state (S1802).

Next, a first PDU session establishment procedure (S1804) is performed.The first PDU session establishment procedure may be an initial PDUsession establishment procedure for establishing the first PDU session.The PDU session to be established may be a single-type PDU session or amulti-type PDU session. More specifically, the PDU session to beestablished may be any one of the first to third single-type PDUsessions or any of the first to third multi-type PDU sessions. Moreover,the first PDU session establishment procedure may be performed accordingto any of a UE-initiated PDU session establishment procedure, a firstnetwork-initiated PDU session establishment procedure and a secondnetwork-initiated PDU session establishment procedure that will bedescribed later.

Here, the first PDU session establishment procedure of the UE-initiatedPDU session establishment procedure may be performed in a case thatestablishment of a UE-initiated single-type PDU session or multi-typePDU session is possible based on the attach procedure.

More specifically, in the attach procedure, the UE_A 10 may start thefirst PDU session establishment procedure, based on the reception of oneor more pieces of identification information among the secondidentification information, the seventeenth identification information,the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information.

The first and second network-initiated PDU session establishmentprocedures may be performed in a case that establishment of anetwork-initiated single-type PDU session or multi-type PDU session ispossible based on the attach procedure.

More specifically, in the attach procedure, the MME_A 40 may start thefirst PDU session establishment procedure, based on transmission of oneor more pieces of identification information among the secondidentification information, the fourth identification information, theseventeenth identification information, the nineteenth identificationinformation, the twenty-first identification information, thetwenty-third identification information, the twenty-fifth identificationinformation, and the twenty-seventh identification information.Alternatively, the MME_A 40 may start the first PDU sessionestablishment procedure, based on the reception of one or more pieces ofidentification information among the first identification information,the third identification information, the fifth identificationinformation, the sixteenth identification information, the eighteenthidentification information, the twentieth identification information,the twenty-second identification information, the twenty-fourthidentification information, and the twenty-sixth identificationinformation.

In a case of requesting PDU session establishment of a single-type PDUsession, the twenty-eighth identification information may be transmittedand/or received in a PDU session establishment request message and/or acreate session request message in the UE-initiated PDU sessionestablishment procedure. Furthermore, in a case that the PDU sessionestablishment of the single-type PDU session is allowed, thetwenty-ninth identification information may be transmitted and/orreceived in a PDU session establishment request message and/or a PDUsession establishment accept message and/or a session response requestmessage and/or a create session response message in the UE-initiated PDUsession establishment procedure.

In a case of requesting PDU session establishment of a multi-type PDUsession, the thirty-sixth identification information may be transmittedand/or received in a PDU session establishment request message and/or acreate session request message in the UE-initiated PDU sessionestablishment procedure. Furthermore, in a case that the PDU sessionestablishment of the multi-type PDU session is allowed, thethirty-seventh identification information may be transmitted and/orreceived in a PDU session establishment request message and/or a PDUsession establishment accept message and/or a session response requestmessage and/or a create session response message in the UE-initiated PDUsession establishment procedure.

In a case of requesting PDU session establishment of the single-type PDUsession, the thirty-second identification information may be transmittedand/or received in a PDU session establishment request message and/or acreate session request message in the first network-initiated PDUsession establishment procedure, or may be transmitted and/or receivedin a first PDU session establishment request message and/or a createsession request message in the second network-initiated PDU sessionestablishment procedure. Furthermore, in a case that the PDU sessionestablishment of single-type PDU session is allowed, the thirty-thirdidentification information may be transmitted and/or received in a PDUsession establishment accept message and/or a create session responsemessage in the first network-initiated PDU session establishmentprocedure, or may be transmitted and/or received in a second PDU sessionestablishment request message and/or a create session response messagein the second network-initiated PDU session establishment procedure.

In a case of requesting PDU session establishment of the multi-type PDUsession, the fortieth identification information may be transmittedand/or received in a PDU session establishment request message and/or acreate session request message in the first network-initiated PDUsession establishment procedure, or may be transmitted and/or receivedin a first PDU session establishment request message and/or a createsession request message in the second network-initiated PDU sessionestablishment procedure. Furthermore, in a case that the PDU sessionestablishment of multi-type PDU session is allowed, the forty-firstidentification information may be transmitted and/or received in a PDUsession establishment accept message and/or a create session responsemessage in the first network-initiated PDU session establishmentprocedure, or may be transmitted and/or received in a second PDU sessionestablishment request message and/or a create session response messagein the second network-initiated PDU session establishment procedure.

Furthermore, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may request, determine, and/orrecognize the type of PDU session to be established, in theabove-described first PDU session establishment procedure. Morespecifically, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may request and/or determine a type ofsingle-type PDU session of the PDU session to be established, based onthe twenty-eighth identification information and/or the thirty-secondidentification information, or may request and/or determine a type ofmulti-type PDU session of the PDU session to be established, based onthe thirty-sixth identification information and/or the fortiethidentification information.

Furthermore, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may recognize a type of a single-typePDU session of the established PDU session, based on the twenty-ninthidentification information and/or the thirty-third identificationinformation, or may recognize a type of multi-type PDU session of theestablished PDU session, based on the thirty-seventh identificationinformation and/or the forty-first identification information.

Moreover, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/or thePGW_A 30 and/or the SCEF_A 46 may select and/or determine an APN and/ora TFT and/or an application and/or a data network and/or a network sliceand/or an access network associated with a PDU session to beestablished, based on various kinds of capability information, in thefirst PDU session establishment procedure.

Note that the first PDU session establishment procedure may be performedin the above-described attach procedure. In this case, the PDU sessionestablishment request message may be transmitted and/or received in anattach request message transmitted from the UE_A 10 to the MME_A 40.Furthermore, the PDU session establishment accept message may betransmitted and/or received in the attach accept message transmittedfrom the MME_A 40 to the UE_A 10. In addition, the PDU sessionestablishment complete message may be transmitted and/or received in anattach complete message transmitted from the UE_A 10 to the MME_A 40.

Through the above-described procedure, the UE_A 10 and/or the MME_A 40and/or the SGW_A 35 and/or the PGW_A 30 and/or the SCEF_A 46 changes tothe second state (S1806).

Next, a second PDU session establishment procedure (S1808) is performed.The second PDU session establishment procedure may be an additional PDUsession establishment procedure for establishing the second PDU session.The PDU session to be established may be a single-type PDU session or amulti-type PDU session. More specifically, the PDU session to beestablished may be any one of the first to third single-type PDUsessions or any of the first to third multi-type PDU sessions.

Moreover, the second PDU session establishment procedure may beperformed according to any of a UE-initiated PDU session establishmentprocedure, a first network-initiated PDU session establishment procedureand a second network-initiated PDU session establishment procedure to bedescribed later.

Here, the second PDU session establishment procedure of the UE-initiatedPDU session establishment procedure may be performed in a case thatUE-initiated establishment of a single-type PDU session or multi-typePDU session is possible based on the attach procedure.

More specifically, the case that UE-initiated establishment of asingle-type PDU session or multi-type PDU session is possible based onthe attach procedure may be a case that the UE_A 10 has received one ormore pieces of identification information among the secondidentification information, the seventeenth identification information,the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information in the attach procedure.

The second PDU session establishment procedure of the first and secondnetwork-initiated PDU session establishment procedures may be performedin a case that network-initiated establishment of a single-type PDUsession or multi-type PDU session is possible based on the attachprocedure.

More specifically, the case that network-initiated establishment of asingle-type PDU session or multi-type PDU session is possible based onthe attach procedure may be a case that the MME_A 40 has transmitted oneor more pieces of identification information among the secondidentification information, the fourth identification information, theseventeenth identification information, the nineteenth identificationinformation, the twenty-first identification information, thetwenty-third identification information, the twenty-fifth identificationinformation, and the twenty-seventh identification information in theattach procedure. Alternatively, the case may be a case that the MME_A40 has received one or more pieces of identification information amongthe first identification information, the third identificationinformation, the fifth identification information, the sixteenthidentification information, the eighteenth identification information,the twentieth identification information, the twenty-secondidentification information, the twenty-fourth identificationinformation, and the twenty-sixth identification information.

Note that, in a case that the second PDU session establishment procedureis a UE-initiated PDU session establishment procedure, the UE_A 10and/or the MME_A 40 and/or the SGW_A 35 and/or the PGW_A 30 and/or theSCEF_A 46 may transmit the thirtieth identification information and/orthe thirty-first identification information and/or thirty-eighthidentification information and/or the thirty-ninth identificationinformation in a message in the UE-initiated PDU session establishmentprocedure that will be described later.

Here, in a case that UE-initiated establishment of a single-type PDUsession or multi-type PDU session is possible based on the attachprocedure, the thirtieth identification information and/or thethirty-first identification information and/or the thirty-eighthidentification information and/or the thirty-ninth identificationinformation may be included in a message in the UE-initiated PDU sessionestablishment procedure.

More specifically, in a case of requesting PDU session establishment ofa single-type PDU session, the thirtieth identification information maybe transmitted and/or received in a PDU session establishment requestmessage and/or a create session request message in the UE-initiated PDUsession establishment procedure. Furthermore, in a case that the PDUsession establishment of the single-type PDU session is allowed, thethirty-first identification information may be transmitted and/orreceived in a PDU session establishment request message and/or a PDUsession establishment accept message and/or a session response requestmessage and/or a create session response message in the UE-initiated PDUsession establishment procedure.

In a case of requesting PDU session establishment of a multi-type PDUsession, the thirty-eighth identification information may be transmittedand/or received in a PDU session establishment request message and/or acreate session request message in the UE-initiated PDU sessionestablishment procedure. Furthermore, in a case that the PDU sessionestablishment of the multi-type PDU session is allowed, the thirty-ninthidentification information may be transmitted and/or received in a PDUsession establishment request message and/or a PDU session establishmentaccept message and/or a session response request message and/or a createsession response message in the UE-initiated PDU session establishmentprocedure.

Furthermore, in a case that the second PDU session establishmentprocedure is a network-initiated PDU session establishment procedure,the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/or the PGW_A 30and/or the SCEF_A 46 may transmit the thirty-fourth identificationinformation and/or the thirty-fifth identification information and/orforty-second identification information and/or the forty-thirdidentification information in a message in the first network-initiatedPDU session establishment procedure and/or a message in the secondnetwork-initiated PDU session establishment procedure that will bedescribed later.

Here, in a case that network-initiated establishment of a single-typePDU session or multi-type PDU session is possible based on the attachprocedure, the thirty-fourth identification information and/or thethirty-fifth identification information and/or the forty-secondidentification information and/or the forty-third identificationinformation may be included in a message in the UE-initiated PDU sessionestablishment procedure.

More specifically, in a case of requesting PDU session establishment ofthe single-type PDU session, the thirty-fourth identificationinformation may be transmitted and/or received in a PDU sessionestablishment request message and/or a create session request message inthe first network-initiated PDU session establishment procedure, or maybe transmitted and/or received in a first PDU session establishmentrequest message and/or a create session request message in the secondnetwork-initiated PDU session establishment procedure. Furthermore, in acase that the PDU session establishment of single-type PDU session isallowed, the thirty-fifth identification information may be transmittedand/or received in a PDU session establishment accept message and/or acreate session response message in the first network-initiated PDUsession establishment procedure, or may be transmitted and/or receivedin a second PDU session establishment request message and/or a createsession response message in the second network-initiated PDU sessionestablishment procedure.

In a case of requesting PDU session establishment of the multi-type PDUsession, the forty-second identification information may be transmittedand/or received in a PDU session establishment request message and/or acreate session request message in the first network-initiated PDUsession establishment procedure, or may be transmitted and/or receivedin a first PDU session establishment request message and/or a createsession request message in the second network-initiated PDU sessionestablishment procedure. Furthermore, in a case that the PDU sessionestablishment of multi-type PDU session is allowed, the forty-thirdidentification information may be transmitted and/or received in a PDUsession establishment accept message and/or a create session responsemessage in the first network-initiated PDU session establishmentprocedure, or may be transmitted and/or received in a second PDU sessionestablishment request message and/or a create session response messagein the second network-initiated PDU session establishment procedure.

Furthermore, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may request, determine, and/orrecognize the type of PDU session to be established, in theabove-described second PDU session establishment procedure. Morespecifically, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may request and/or determine a type ofsingle-type PDU session of the PDU session to be established, based onthe thirtieth identification information and/or the thirty-fourthidentification information, or may request and/or determine a type ofmulti-type PDU session of the PDU session to be established, based onthe thirty-eighth identification information and/or the forty-secondidentification information.

Furthermore, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may recognize a type of a single-typePDU session of the established PDU session, based on the thirty-firstidentification information and/or the thirty-fifth identificationinformation, or may recognize a type of multi-type PDU session of theestablished PDU session, based on the thirty-ninth identificationinformation and/or the forty-third identification information.

Furthermore, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may release the PDU sessionestablished in the first PDU session establishment procedure and/or thePDU session currently used for the communication, based on thethirty-first identification information and/or the thirty-fifthidentification information, or may maintain, instead of releasing, thePDU session established in the first PDU session establishment procedureand/or the PDU session currently used for the communication, based onthe thirty-ninth identification information and/or the forty-thirdidentification information.

Moreover, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/or thePGW_A 30 and/or the SCEF_A 46 may select and/or determine an APN and/ora TFT and/or an application and/or a data network and/or a network sliceand/or an access network associated with a PDU session to beestablished, based on various kinds of capability information, in thesecond PDU session establishment procedure.

Note that, in a case that the second single-type PDU session or thesecond multi-type PDU session has been established, the APN and/or theTFT and/or the application and/or the data network and/or the networkslice and/or the access network selected and/or determined in the secondPDU session establishment procedure may be the same as those selectedand/or determined in the first PDU session establishment procedure.

In a case that the third single-type PDU session or the third multi-typePDU session has been established, the APN and/or the TFT and/or theapplication and/or the data network and/or the network slice and/or theaccess network selected and/or determined in the second PDU sessionestablishment procedure may be different from those selected and/ordetermined in the first PDU session establishment procedure.

The UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/or the PGW_A 30and/or the SCEF_A 46 may update information for controlling transmissionand/or reception of user data, following the second PDU sessionestablishment procedure. Specifically, based on the second PDU sessionestablishment procedure, each apparatus may change a PDU session to beused for transmission and/or reception of user data to a PDU sessionestablished in the second PDU session establishment procedure. Note thatinformation for controlling transmission and/or reception of user datamay be a TFT.

Moreover, in a case that the PDU session to be established is asingle-type PDU session, each apparatus may release the PDU sessionestablished before performing the second PDU session establishmentprocedure, in a case of update of the information for controllingtransmission and/or reception of user data. More specifically, eachapparatus may delete the context related to the already-established PDUsession in a case of update of the information for controllingtransmission and/or reception of user data.

Note that, in a case that the PDU session to be established is amulti-type PDU session, update of the information for controllingtransmission and/or reception of user data may be performed by a flowswitching procedure (S1810) instead of being performed with the secondPDU session establishment procedure. The flow switching procedure is aprocedure for switching a PDU session to be used for transmission and/orreception of user data.

The UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/or the PGW_A 30and/or the SCEF_A 46 may change a PDU session to be used fortransmission and/or reception of user data to a PDU session establishedin the second PDU session establishment procedure, based on the flowswitching procedure.

The flow switching procedure may include a UE-initiated flow switchingprocedure and a network-initiated flow switching procedure. Details ofthe flow switching procedure will be described later.

Through the above-described procedure, the UE_A 10 and/or the MME_A 40and/or the SGW_A 35 and/or the PGW_A 30 and/or the SCEF_A 46 changes tothe third state (S1812).

1.3.1. Attach Procedure Example

First, an example of an attach procedure will be described.

The attach procedure is a procedure which is started on the initiativeof the UE_A 10. The attach procedure is a procedure for the UE_A 10 toconnect to a network. In other words, the attach procedure is aprocedure for connecting to an access network, and is a procedure forfurther connecting to a core network through the access network.

A trigger when the UE_A 10 starts the attach procedure may be a timewhen the terminal is switched on, or the like. The UE_A 10 may start atan arbitrary timing in a case that the UE_A 10 is not connected to thecore network_A 90 regardless of the above.

Moreover, the UE_A 10 may, or may not necessarily, establish a PDUsession with the core network_A 90 in a case of completion of the attachprocedure. In other words, the UE_A 10 may, or may not necessarily,establish a PDU session with the PGW_A 30 and/or the SCEF_A 46 in a caseof completion of the attach procedure.

Note that, in a case that a PDU session is established in the attachprocedure, a message in the first PDU session establishment procedurethat will be described later may be transmitted and/or received togetherwith a message in the attach procedure.

Hereinafter, the steps of the attach procedure will be described withreference to FIG. 19.

First, the UE_A 10 transmits an attach request message to the MME_A 40(S1900). Note that the UE_A 10 may transmit the attach request messageto an apparatus in an access network, and the transmitted attach requestmessage may be transferred to the MME_A 40 via the apparatus in theaccess network.

Note that selection of an access network and/or an apparatus in anaccess network may be performed based on information held by the UE_A 10or may be performed based on information received from a network inadvance.

Additionally, the UE_A 10 may transmit a PDU session establishmentrequest message with the attach request message. Hereinafter, in thedescription of the present embodiment, the attach request message isdescribed as a message in which the attach request message and the PDUsession establishment request message are combined. Furthermore, in thedescription of this procedure, in a case that an expression“identification information is included in the attach request message”is used, the expression means that the identification information isincluded in the attach request message and/or the PDU sessionestablishment request message.

The UE_A 10 may transmit, in the attach request message, one or morepieces of identification information among the first identificationinformation, the third identification information, the fifthidentification information, the sixteenth identification information,the eighteenth identification information, the twentieth identificationinformation, the twenty-second identification information, thetwenty-fourth identification information, and the twenty-sixthidentification information at least. The UE_A 10 may indicate that thenetwork-initiated PDU session establishment procedure is supported ormay indicate capability of supported Service Continuity, by transmittingthe attach request message including one or more pieces ofidentification information among the first identification information,the third identification information, the fifth identificationinformation, the sixteenth identification information, the eighteenthidentification information, the twentieth identification information,the twenty-second identification information, the twenty-fourthidentification information, and the twenty-sixth identificationinformation.

Here, the UE_A 10 may transmit one or more pieces of identificationinformation among the first identification information, the thirdidentification information, the fifth identification information, thesixteenth identification information, the eighteenth identificationinformation, the twentieth identification information, the twenty-secondidentification information, the twenty-fourth identificationinformation, and the twenty-sixth identification information in acontrol message different from the attach request message in the attachprocedure, instead of transmitting the one or more pieces ofidentification information in the attach request message to the MME_A40.

For example, after transmitting the attach request message, the UE_A 10may perform a request of EPS Session Management (ESM) information, and atransmission and/or reception procedure of a control message whichresponds based on the request (S1902).

To be more specific, the MME_A 40 transmits an ESM request message tothe UE_A 10. The UE_A 10 receives the ESM request message and transmitsa response message to the MME_A 40. In this operation, the UE_A 10 maytransmit, in the response message, one or more pieces of identificationinformation among the first identification information, the thirdidentification information, the filth identification information, thesixteenth identification information, the eighteenth identificationinformation, the twentieth identification information, the twenty-secondidentification information, the twenty-fourth identificationinformation, and the twenty-sixth identification information.

Here, the UE_A 10 may encrypt and transmit the ESM response message.Furthermore, the UE_A 10 may receive information for encrypting the ESMresponse message from the MME_A 40. The MME_A 40 may transmitinformation for encrypting a NAS message to the UE_A 10 with thereception of the attach request message. Note that the NAS message forwhich the information for encrypting the NAS message is transmitted maybe a Security Mode Command message.

The MME_A 40 receives the attach request message. Furthermore, the MME_A40 acquires one or more pieces of identification information among thefirst identification information, the third identification information,the fifth identification information, the sixteenth identificationinformation, the eighteenth identification information, the twentiethidentification information, the twenty-second identificationinformation, the twenty-fourth identification information, and thetwenty-sixth identification information, based on the reception of theattach request message or the reception of the ESM response message.Note that the MME_A 40 may store the acquired identificationinformation.

The MME_A 40 may select and/or determine a type of PDU session that canbe established, or may be determine whether or not to establish a PDUsession in the attach procedure, based on information included in theattach request message and/or subscriber information and/or an operatorpolicy and/or identification information held by the MME_A 40.

Furthermore, the MME_A 40 may determine to establish the PDU session inthe attach procedure, by receiving, with the attach request message, asession establishment request message that will be described latertogether with the UE-initiated session establishment procedure or anypiece of identification information included in the sessionestablishment request message. In other cases, the MME_A 40 maydetermine not to establish the PDU session in the attach procedure.

In a case of establishing a PDU session in the attach procedure, theMME_A 40 may select and/or determine an apparatus to be used in the PDUsession, based on information included in the attach request messageand/or subscriber information and/or an operator policy and/oridentification information held by the MME_A 40. Specifically, the MME_A40 may select the SGW_A 35 and/or the PGW_A 30 as a destination of thePDU session establishment or may select the SCEF_A 46 as a destinationof the PDU session establishment.

Note that, in a case of establishing a PDU session with the PGW_A 30,the MME_A 40 performs the procedure from S1904 to S1912 with the SGW_A35 and/or the PGW_A 30.

Specifically, in a case of establishing a PDU session with the PGW_A 30,the MME_A 40 transmits a create session request message to the SGW_A 35(S1904). The MME_A 40 may transmit, in the create session requestmessage, one or more pieces of identification information among thefirst identification information to the fifth identification informationand/or the sixteenth identification information to the twenty-seventhidentification information at least.

The SGW_A 35 receives the create session request message transmittedfrom the MME_A 40. Furthermore, the SGW_A 35 acquires one or more piecesof identification information among the first identification informationto the fifth identification information and/or the sixteenthidentification information to the twenty-seventh identificationinformation, based on the reception of the create session requestmessage. Note that the SGW_A 35 may store the acquired identificationinformation.

Based on the reception of the create session request message, the SGW_A35 transmits the create session request message to the PGW_A 30 (S1906).The SGW_A 35 may transmit, in the create session request message, one ormore pieces of identification information among the first identificationinformation to the fifth identification information and/or the sixteenthidentification information to the twenty-seventh identificationinformation at least.

The PGW_A 30 receives the create session request message transmittedfrom the SGW_A 35. Furthermore, the PGW_A 30 acquires one or more piecesof identification information among the first identification informationto the fifth identification information and/or the sixteenthidentification information to the twenty-seventh identificationinformation, based on the reception of the create session requestmessage. Note that the PGW_A 30 may store the acquired identificationinformation.

Based on the reception of the create session request message, the PGW_A30 transmits a create session response message to the SGW_A 35 (S1910).The PGW_A 30 may transmit, in the create session response message, oneor more pieces of identification information among the secondidentification information, the fourth identification information, theseventeenth identification information, the nineteenth identificationinformation, the twenty-first identification information, thetwenty-third identification information, the twenty-fifth identificationinformation, and the twenty-seventh identification information at least.

The SGW_A 35 receives the create session response message transmittedfrom the PGW_A 30. Furthermore, the SGW_A 35 acquires one or more piecesof identification information among the first identification informationto the fifth identification information and/or the sixteenthidentification information to the twenty-seventh identificationinformation, based on the reception of the create session responsemessage. Note that the SGW_A 35 may store the acquired identificationinformation.

Based on the reception of the create session response message, the SGW_A35 transmits the create session response message to the MME_A 40(S1912). The SGW_A 35 may transmit, in the create session responsemessage, one or more pieces of identification information among thefirst identification information to the fifth identification informationand/or the sixteenth identification information to the twenty-seventhidentification information at least.

The MME_A 40 receives the create session response message transmittedfrom the SGW_A 35. Furthermore, the MME_A 40 acquires one or more piecesof identification information among the first identification informationto the fifth identification information and/or the sixteenthidentification information to the twenty-seventh identificationinformation, based on the reception of the create session responsemessage. Note that the MME_A 40 may store the acquired identificationinformation.

In a case of establishing a PDU session with the SCEF_A 46, the MME_A 40performs the procedure from S1914 to S1916 with the SCEF_A 46.

Specifically, in a case of establishing a PDU session with the SCEF_A46, the MME_A 40 transmits a create session request message to theSCEF_A 46 (S1914). The MME_A 40 may transmit, in the create sessionrequest message, one or more pieces of identification information amongthe first identification information to the fifth identificationinformation and/or the sixteenth identification information to thetwenty-seventh identification information at least.

The SCEF_A 46 receives the create session request message transmittedfrom the MME_A 40. Furthermore, the SCEF_A 46 acquires one or morepieces of identification information among the first identificationinformation to the fifth identification information and/or the sixteenthidentification information to the twenty-seventh identificationinformation, based on the reception of the create session requestmessage. Note that the SCEF_A 46 may store the acquired identificationinformation.

Based on the reception of the create session request message, the SCEF_A46 transmits the create session request message to the MME_A 40 (S1916).The SCEF_A 46 may transmit, in the create session response message, oneor more pieces of identification information among the firstidentification information to the fifth identification informationand/or the sixteenth identification information to the twenty-seventhidentification information at least.

The MME_A 40 receives the create session response message transmittedfrom the SCEF_A 46. Furthermore, the MME_A 40 acquires one or morepieces of identification information among the first identificationinformation to the fifth identification information and/or the sixteenthidentification information to the twenty-seventh identificationinformation, based on the reception of the create session responsemessage. Note that the MME_A 40 may store the acquired identificationinformation.

Note that, in a case of not establishing a PDU session in the attachprocedure, the MME_A 40 may not necessarily perform the procedure fromS1904 to S1916.

Based on the reception of the attach request message, and/or selectionand/or determination of a type of PDU session that can be established,and/or the reception of the create session response message, the MME_A40 transmits an attach accept message to the apparatus in the accessnetwork (S1918).

The MME_A 40 may transmit PDU session establishment accept together withthe attach accept message. Hereinafter, in the description of thisprocedure, the attach accept message is described as a message in whichthe attach accept message and the PDU session establishment accept arecombined. Furthermore, in the description of this procedure, in a casethat an expression “identification information is included in the attachaccept message” is used, the expression means that the identificationinformation is included in the attach accept message and/or the PDUsession establishment accept.

The MME_A 40 may include, in the attach accept message, one or morepieces of identification information among the second identificationinformation, the fourth identification information, the seventeenthidentification information, the nineteenth identification information,the twenty-first identification information, the twenty-thirdidentification information, the twenty-fifth identification information,and the twenty-seventh identification information at least.

Note that the attach accept message may be a response message to theattach request message.

The apparatus in the access network receives the attach accept message,and transmits an RRC message including the attach accept message to theUE_A 10 (S1920). Note that the RRC message may be an RRC connectionreconfiguration request message or a direct transfer message.Alternatively, the RRC message may be another message between the accessnetwork and the UE_A 10.

The UE_A 10 receives the RRC message including the attach acceptmessage. Furthermore, in a case that one or more pieces ofidentification information among the second identification information,the fourth identification information, the seventeenth identificationinformation, the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information are included in the attach accept message,the UE_A 10 acquires the included pieces of identification information.Note that the UE_A 10 may store the acquired pieces of identificationinformation.

Based on the reception of the attach accept message and/or informationincluded in the attach accept message, the UE_A 10 may recognize whetheror not the network-initiated PDU session establishment procedure issupported, may recognize the type of supported access network, or mayrecognize the type of supported Service Continuity.

More specifically, the UE_A 10 may recognize that the network-initiatedsession establishment procedure is supported, based on the fourthidentification information.

The UE_A 10 may recognize a supported access network, based on thesecond identification information.

The UE_A 10 may recognize that establishment of the first single-typePDU session is supported, based on the seventeenth identificationinformation, may recognize that establishment of the second single-typePDU session is supported, based on the nineteenth identificationinformation, or may recognize that establishment of the thirdsingle-type PDU session is supported, based on the twenty-firstidentification information.

Furthermore, the UE_A 10 may recognize that establishment of the firstmulti-type PDU session is supported, based on the twenty-thirdidentification information, may recognize that establishment of thesecond multi-type PDU session is supported, based on the twenty-fifthidentification information, or may recognize that establishment of thethird multi-type PDU session is supported, based on the twenty-seventhidentification information.

In order to respond to the received RRC message, the UE_A 10 transmitsthe RRC message to the apparatus in the access network (S1922). The RRCmessage may be an RRC connection reconfiguration complete message.

The apparatus in the access network receives an RRC connectionreconfiguration message and transmits a bearer configuration message tothe MME_A 40, based on the reception (S1924).

Note that, in a case of not establishing a PDU session in the attachprocedure, the procedure from S1922 to S1924 may be omitted.

The UE_A 10 transmits an RRC message including an attach completemessage to the apparatus in the access network, based on the receptionof the attach accept message (S1926). Here, the attach complete messagemay be a response message to the attach accept message. Note that theRRC message to be transmitted while including the attach completemessage may be a Direct Transfer message.

The apparatus in the access network receives the RRC message includingthe attach complete message and transmits the attach complete message tothe MME_A 40 (S1928).

The MME_A 40 receives the attach complete message.

The MME_A 40 may transmit a modify bearer request message to the SGW_A35, based on the reception of the attach complete message (S1930).

The SGW_A 35 receives the modify bearer request message.

The SGW_A 35 may transmit a modify bearer response message to the MME_A40, based on the reception of the modify bearer request message (S1932).

Note that the modify bearer request message may be a response message tothe modify bearer request message.

The MME_A 40 receives the modify bearer response message.

By the above-described steps, the UE_A 10 connects to the network, andcompletes the attach procedure. With the completion of the attachprocedure, the UE_A 10 and/or the core network_A 90 can recognize andstore whether or not the network-initiated session establishmentprocedure is supported, and/or the type of supported access networkand/or the type of supported Service Continuity.

1.3.2. Examples of PDU Session Establishment Procedure

Next, examples of the PDU session establishment procedure will bedescribed.

The PDU session establishment procedure includes a UE-initiated PDUsession establishment procedure, which starts under the initiative ofthe UE_A 10, and a network-initiated PDU session establishmentprocedure. Note that the PDU session establishment procedure is aprocedure in which the UE_A 10 establishes a PDU session to be used fortransmission and/or reception of user data, with the core network_A 90.The UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/or the PGW_A 30and/or the SCEF_A 46 establishes a communication path for transmissionand/or reception of user data with the data network, through the PDUsession establishment procedure.

Note that the PDU session establishment procedure may be performed atany timing after the attach. Moreover, the PDU session establishmentprocedure under the initiative of the UE_A 10 may be performed in theattach procedure performed at initial connection to the core network A_A90, for example, when the terminal is switched on. The network-initiatedPDU session establishment procedure may be performed based on thereception of user data and/or a control message from the data network bythe PGW_A 30 and/or the SCEF_A 46, or may be performed based on updateof the operator policy.

The UE_A 10 establishes the PDU session with the PGW_A 30 and/or theSCEF_A 46 in a case of completion of the PDU session establishmentprocedure. Note that the UE_A 10 and/or the core network_A 90 canestablish multiple PDU sessions by performing the PDU sessionestablishment procedure multiple times.

The UE_A 10 and/or the core network_A 90 performs the PDU sessionestablishment procedure by including, in individual messages,identification information indicating an APN and/or a TFT and/or anapplication and/or a data network and/or a network slice and/or anaccess network different from those associated with the established PDUsession, and can thereby newly establish a PDU session with thedifferent APN and/or TFT and/or application and/or data network and/ornetwork slice and/or access network corresponding to that included theindividual message.

Alternatively, the UE_A 10 and/or the core network_A 90 performs the PDUsession establishment procedure by including, in individual messages,identification information indicating an APN and/or a TFT and/or anapplication and/or a data network and/or a network slice and/or anaccess network that are the same as those associated with theestablished PDU session, and can thereby newly establish a PDU sessionwith the same APN and/or TFT and/or application and/or data networkand/or network slice and/or access network corresponding to thatincluded the individual message.

1.3.2.1. Example of UE-Initiated PDU Session Establishment Procedure

Next, an example of steps of the UE-initiated PDU session procedure willbe described with reference to FIG. 20.

Note that the UE-initiated PDU session establishment procedure is aprocedure for establishing a PDU session with the PGW_A 30 and/or theSCEF_A 46 under the initiative of the UE.

First, the UE_A 10 selects an access network to be used to establish aPDU session. Note that, for the selection of an access network, the UE_A10 may use information acquired from a network in the attach procedure,may use information acquired from a network outside the attachprocedure, or may use information stored in the UE_A 10.

Next, the UE_A 10 initiates the UE-initiated PDU session establishmentprocedure by transmitting a PDU session establishment request message tothe MME_A 40 via the selected access network to start (S2000). Note thatthe UE_A 10 may transmit the PDU session establishment request messageto an apparatus in the selected access network, and the transmitted PDUsession establishment request message may be transferred to the MME_A 40via the apparatus in the selected access network.

The UE_A 10 may include, in the PDU session establishment requestmessage, one or more pieces of identification information among thefirst identification information, the sixth identification information,the seventh identification information, the eighth identificationinformation, the ninth identification information, the tenthidentification information, the sixteenth identification information,the eighteenth identification information, the twentieth identificationinformation, the twenty-second identification information, thetwenty-fourth identification information, and the twenty-sixthidentification information, and transmit them.

The UE_A 10 may indicate capability of supported Service Continuity bytransmitting the PDU session establishment request message including oneor more pieces of identification information among the sixteenthidentification information, the eighteenth identification information,the twentieth identification information, the twenty-secondidentification information, the twenty-fourth identificationinformation, and the twenty-sixth identification information. The UE_A10 may request in more detail the type of PDU session to be established,by transmitting the PDU session establishment request message includingone or more pieces of identification information among the sixthidentification information to the tenth identification information.

The MME_A 40 receives the PDU session establishment request messagetransmitted from the UE_A 10. Furthermore, based on the reception of thePDU session establishment request message, the MME_A 40 acquires one ormore pieces of identification information among the first identificationinformation, the sixth identification information, the seventhidentification information, the eighth identification information, theninth identification information, the tenth identification information,the sixteenth identification information, the eighteenth identificationinformation, the twentieth identification information, the twenty-secondidentification information, the twenty-fourth identificationinformation, and the twenty-sixth identification information. Note thatthe MME_A 40 may store the acquired identification information.

Based on the reception of the PDU session establishment request messageand/or information included in the PDU session establishment requestmessage, the MME_A 40 may recognize the type of supported ServiceContinuity or may recognize that the PDU session has been established.

More specifically, the MME_A 40 may recognize that establishment of thefirst single-type PDU session is supported by the UE_A 10, based on thesixteenth identification information, may recognize that establishmentof the second single-type PDU session is supported by the UE_A 10, basedon the eighteenth identification information, or may recognize thatestablishment of the third single-type PDU session is supported by theUE_A 10, based on the twentieth identification information.

Furthermore, the MME_A 40 may recognize that establishment of the firstmulti-type PDU session is supported by the UE_A 10, based on thetwenty-second identification information, may recognize thatestablishment of the second multi-type PDU session is supported by theUE_A 10, based on the twenty-fourth identification information, or mayrecognize that establishment of the third multi-type PDU session issupported by the UE_A 10, based on the twenty-sixth identificationinformation.

The MME_A 40 may recognize in more detail the type of PDU sessionrequested by the UE_A 10 to establish, based on one or more pieces ofidentification information among the sixth identification information tothe tenth identification information. For example, the MME_A 40 mayrecognize the IP address allocated to the UE_A 10, based on the seventhidentification information.

The MME_A 40 may store one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information in association with the PDU session to beestablished. In other words, the PDU session to be established may beassociated with the one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information. For example, the PDU session to beestablished may be associated with the IP address allocated to the UE_A10.

The MME_A 40 may select and/or determine a type of PDU session that canbe established, based on information included in the PDU sessionestablishment request message and/or subscriber information and/or anoperator policy and/or identification information held by the MME_A 40.

The MME_A 40 may select and/or determine an apparatus used for a PDUsession to be established, based on information included in the PDUsession establishment request message and/or subscriber informationand/or an operator policy and/or identification information held by theMME_A 40. Specifically, the MME_A 40 may select the SGW_A 35 and/or thePGW_A 30 as a destination of the PDU session establishment or may selectthe SCEF_A 46 as a destination of the PDU session establishment.

Here, in a case of establishing a PDU session with the PGW_A 30, theMME_A 40 performs the procedures from S2002 to S2008 with the SGW_A 35and/or the PGW_A 30.

Specifically, in a case of establishing a PDU session with the PGW_A 30,the MME_A 40 transmits a create session request message to the SGW_A 35(S2002). The MME_A 40 may transmit, in the create session requestmessage, one or more pieces of identification information among thesixth identification information to the twenty-seventh identificationinformation at least.

The SGW_A 35 receives the create session request message transmittedfrom the MME_A 40. Furthermore, the SGW_A 35 acquires one or more piecesof identification information among the sixth identification informationto the twenty-seventh identification information, based on the receptionof the create session request message. Note that the SGW_A 35 may storethe acquired identification information.

Based on the reception of the create session request message, the SGW_A35 transmits the create session request message to the PGW_A 30 (S2004).The SGW_A 35 may transmit, in the create session request message, one ormore pieces of identification information among the sixth identificationinformation to the twenty-seventh identification information at least.

The PGW_A 30 receives the create session request message transmittedfrom the SGW_A 35. Furthermore, the PGW_A 30 acquires one or more piecesof identification information among the sixth identification informationto the twenty-seventh identification information, based on the receptionof the create session request message. Note that the PGW_A 30 may storethe acquired identification information.

Based on the reception of the create session request message, the PGW_A30 transmits a create session response message to the SGW_A 35 (S2006).The PGW_A 30 may transmit, in the create session response message, oneor more pieces of identification information among the eleventhidentification information, the twelfth identification information, thethirteenth identification information, the fourteenth identificationinformation, the fifteenth identification information, the seventeenthidentification information, the nineteenth identification information,the twenty-first identification information, the twenty-thirdidentification information, the twenty-fifth identification information,and the twenty-seventh identification information at least.

The SGW_A 35 receives the create session response message transmittedfrom the PGW_A 30. Furthermore, based on the reception of the createsession response message, the SGW_A 35 acquires one or more pieces ofidentification information among the eleventh identificationinformation, the twelfth identification information, the thirteenthidentification information, the fourteenth identification information,the fifteenth identification information, the seventeenth identificationinformation, the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information. Note that the SGW_A 35 may store theacquired identification information.

Based on the reception of the create session response message, the SGW_A35 transmits the create session response message to the MME_A 40(S2008). The SGW_A 35 may transmit, in the create session responsemessage, one or more pieces of identification information among theeleventh identification information, the twelfth identificationinformation, the thirteenth identification information, the fourteenthidentification information, the fifteenth identification information,the seventeenth identification information, the nineteenthidentification information, the twenty-first identification information,the twenty-third identification information, the twenty-fifthidentification information, and the twenty-seventh identificationinformation at least.

The MME_A 40 receives the create session response message transmittedfrom the SGW_A 35. Furthermore, based on the reception of the createsession response message, the MME_A 40 acquires one or more pieces ofidentification information among the eleventh identificationinformation, the twelfth identification information, the thirteenthidentification information, the fourteenth identification information,the fifteenth identification information, the seventeenth identificationinformation, the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information. Note that the MME_A 40 may store theacquired identification information.

In a case of establishing a PDU session with the SCEF_A 46, the MME_A 40performs the procedure from S2010 to S2012 with the SCEF_A 46.

Specifically, in a case of establishing a PDU session with the SCEF_A46, the MME_A 40 transmits a create session request message to theSCEF_A 46 (S2010). The MME_A 40 may transmit, in the create sessionrequest message, one or more pieces of identification information amongthe sixth identification information to the twenty-seventhidentification information at least.

The SCEF_A 46 receives the create session request message transmittedfrom the MME_A 40. Furthermore, the SCEF_A 46 acquires one or morepieces of identification information among the sixth identificationinformation to the twenty-seventh identification information, based onthe reception of the create session request message. Note that theSCEF_A 46 may store the acquired identification information.

Based on the reception of the create session request message, the SCEF_A46 transmits the create session request message to the MME_A 40 (S2012).The SCEF_A 46 may transmit, in the create session response message, oneor more pieces of identification information among the eleventhidentification information, the twelfth identification information, thethirteenth identification information, the fourteenth identificationinformation, the fifteenth identification information, the seventeenthidentification information, the nineteenth identification information,the twenty-first identification information, the twenty-thirdidentification information, the twenty-fifth identification information,and the twenty-seventh identification information at least.

The MME_A 40 receives the create session response message transmittedfrom the SCEF_A 46. Furthermore, based on the reception of the createsession response message, the MME_A 40 acquires one or more pieces ofidentification information among the eleventh identificationinformation, the twelfth identification information, the thirteenthidentification information, the fourteenth identification information,the fifteenth identification information, the seventeenth identificationinformation, the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information. Note that the MME_A 40 may store theacquired identification information.

Based on the reception of the PDU session establishment request messageand/or selection and/or determination of a type of PDU session that canbe established and/or the reception of the create session responsemessage, the MME_A 40 transmits a PDU session establishment acceptmessage to an apparatus in the access network (S2014).

The MME_A 40 may include, in the PDU session establishment acceptmessage, one or more pieces of identification information among theeleventh identification information, the twelfth identificationinformation, the thirteenth identification information, the fourteenthidentification information, the fifteenth identification information,the seventeenth identification information, the nineteenthidentification information, the twenty-first identification information,the twenty-third identification information, the twenty-fifthidentification information, and the twenty-seventh identificationinformation at least.

Note that the PDU session establishment accept message may be a responsemessage to the PDU session establishment request message.

The apparatus in the access network receives the PDU sessionestablishment accept message and transmits an RRC message including thePDU session establishment accept message to the UE_A 10 (S2016). Notethat the RRC message may be an RRC connection reconfiguration requestmessage. Alternatively, the RRC message may be another message betweenthe access network and the UE_A 10.

The UE_A 10 receives the RRC message including the PDU sessionestablishment accept message. Furthermore, in a case that one or morepieces of identification information among the eleventh identificationinformation, the twelfth identification information, the thirteenthidentification information, the fourteenth identification information,the fifteenth identification information, the seventeenth identificationinformation, the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information are included in the PDU session establishmentaccept message, the UE_A 10 acquires the included pieces ofidentification information. Note that the UE_A 10 may store the acquiredpieces of identification information.

Based on the reception of the PDU session establishment accept messageand/or information included in the PDU session establishment acceptmessage, the UE_A 10 may recognize the type of supported ServiceContinuity or may recognize that the PDU session has been established.

More specifically, the UE_A 10 may recognize that establishment of thefirst single-type PDU session is supported by a network, based on theseventeenth identification information, may recognize that establishmentof the second single-type PDU session is supported by a network, basedon the nineteenth identification information, or may recognize thatestablishment of the third single-type PDU session is supported by anetwork, based on the twenty-first identification information.

Furthermore, the UE_A 10 may recognize that establishment of the firstmulti-type PDU session is supported by a network, based on thetwenty-third identification information, may recognize thatestablishment of the second multi-type PDU session is supported by anetwork, based on the twenty-fifth identification information, or mayrecognize that establishment of the third multi-type PDU session issupported by a network, based on the twenty-seventh identificationinformation.

The UE_A 10 may recognize in more detail the type of established PDUsession, based on one or more pieces of identification information amongthe eleventh identification information to the fifteenth identificationinformation. For example, the UE_A 10 may recognize the IP addressallocated to the UE_A 10, based on the twelfth identificationinformation.

The UE_A 10 may store one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information in association with the PDU session to beestablished. In other words, the PDU session to be established may beassociated with the one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information. For example, the PDU session to beestablished may be associated with the IP address allocated to the UE_A10.

In order to respond to the received RRC message, the UE_A 10 maytransmit the RRC message to an apparatus in the access network (S2018).The RRC message may be an RRC connection reconfiguration completemessage.

The apparatus in the access network may receive the RRC connectionreconfiguration message and transmit a bearer configuration message tothe MME_A 40, based on the reception (S2020).

The UE_A 10 transmits the RRC message including a PDU sessionestablishment complete message to an apparatus in the access network,based on the reception of the PDU session establishment accept message(S2022). Here, the PDU session establishment complete message may be aresponse message to the PDU session establishment accept message. Notethat the RRC message to be transmitted while including the PDU sessionestablishment complete message may be a Direct Transfer message.

The apparatus in the access network receives the RRC message includingthe PDU session establishment complete message and transmits the PDUsession establishment complete message to the MME_A 40 (S2024).

The MME_A 40 receives the PDU session establishment complete message.

The MME_A 40 may transmit a modify bearer request message to the SGW_A35, based on the reception of the PDU session establishment completemessage (S2026).

The SGW_A 35 receives the modify bearer request message.

The SGW_A 35 may transmit a modify bearer response message to the MME_A40, based on the reception of the modify bearer request message (S2028).

Note that the modify bearer request message may be a response message tothe modify bearer request message.

The MME_A 40 receives the modify bearer response message.

Through the above steps, the UE-initiated PDU session establishmentprocedure is completed. With the completion of the UE-initiated PDUsession establishment procedure, the UE_A 10 and/or the core network_A90 can establish the PDU session. Moreover, with the completion of theUE-initiated PDU session establishment procedure, the UE_A 10 and/or thecore network_A 90 can recognize and store the type of supported ServiceContinuity.

Specifically, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may recognize that establishment ofthe first single-type PDU session is supported, based on the sixteenthidentification information and/or the seventeenth identificationinformation, may recognize that establishment of the second single-typePDU session is supported, based on the eighteenth identificationinformation and/or the nineteenth identification information, or mayrecognize that establishment of the third single-type PDU session issupported, based on the twentieth identification information and/or thetwenty-first identification information.

Furthermore, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may recognize that establishment ofthe first multi-type PDU session is supported, based on thetwenty-second identification information and/or the twenty-thirdidentification information, may recognize that establishment of thesecond multi-type PDU session is supported, based on the twenty-fourthidentification information and/or the twenty-fifth identificationinformation, or may recognize that establishment of the third multi-typePDU session is supported, based on the twenty-sixth identificationinformation and/or the twenty-seventh identification information.

1.3.2.2. Examples of Network-Initiated PDU Session EstablishmentProcedure

Next, examples of the steps of the network-initiated PDU sessionestablishment procedure will be described. Note that thenetwork-initiated PDU session establishment procedure is a procedure forestablishing a PDU session between the UE_A 10 and the PGW_A 30 and/orthe SCEF_A 46 under the initiative of the PGW_A 30 and/or the SCEF_A 46and/or the MME_A 40. The network-initiated PDU session establishmentprocedure may include a first network-initiated PDU sessionestablishment procedure and a second network-initiated PDU sessionestablishment procedure.

1.3.2.2.1. Example of First Network-Initiated PDU Session EstablishmentProcedure

Next, an example of the steps of the first network-initiated PDU sessionestablishment procedure will be described with reference to FIG. 21. Thefirst network-initiated PDU session establishment procedure is aprocedure in which the core network_A 90 selects an access network to beused for establishment of a PDU session and establishes a PDU sessionwith the UE_A 10.

The first network-initiated PDU session establishment procedure includesa PGW_A 30 initiated procedure, a SCEF_A 46 initiated procedure, and aMME_A 40 initiated procedure. Note that the procedure in S2100 to S2102is performed in the PGW_A 30 initiated procedure, while the procedure inS2104 to S2106 is performed in the SCEF_A 46 initiated procedure.Moreover, in the MME_A 40 initiated procedure, the procedure is startedfrom S2108 without performing the procedure in S2100 to S2106.Alternatively, the MME_A 40 may transmit a control message for creatinga session under the initiative of a network to the PGW_A 30, and thePGW_A may start the PGW_A 30 initiated procedure, based on the receptionof the control message transmitted from the MME_A 40. Similarly, theMME_A 40 may transmit a control message for creating a session under theinitiative of a network to the SCEF_A 46, and the SCEF_A 46 may startthe SCEF_A 46 initiated procedure, based on the reception of the controlmessage transmitted from the MME_A 40. In this case, the MME_A 40 mayperform a process of selecting an access network (S2108) before thetransmission of the control message. Note that the MME_A 40 maytransmit, in the control message, one or more pieces of identificationinformation among the second identification information, the sixthidentification information, the seventh identification information, theeighth identification information, the ninth identification information,the tenth identification information, the seventeenth identificationinformation, the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information at least.

First, a description will be given of the steps of the procedure fromS2100 to S2106.

In a case of the PGW_30 initiated procedure, the PGW_A 30 transmits acreate session request message to the SGW_A 35 (S2100). The PGW_A 30 maytransmit, in the create session request message, one or more pieces ofidentification information among the second identification information,the sixth identification information, the seventh identificationinformation, the eighth identification information, the ninthidentification information, the tenth identification information, theseventeenth identification information, the nineteenth identificationinformation, the twenty-first identification information, thetwenty-third identification information, the twenty-fifth identificationinformation, and the twenty-seventh identification information at least.

The SGW_A 35 receives the create session request message transmittedfrom the PGW_A 30. Furthermore, based on the reception of the createsession request message, the SGW_A 35 acquires one or more pieces ofidentification information among the second identification information,the sixth identification information, the seventh identificationinformation, the eighth identification information, the ninthidentification information, the tenth identification information, theseventeenth identification information, the nineteenth identificationinformation, the twenty-first identification information, thetwenty-third identification information, the twenty-fifth identificationinformation, and the twenty-seventh identification information. Notethat the SGW_A 35 may store the acquired identification information.

The SGW_A 35 transmits the create session request message to the MME_A40 (S2102). The SGW_A 35 may transmit, in the create session requestmessage, one or more pieces of identification information among thesecond identification information, the sixth identification information,the seventh identification information, the eighth identificationinformation, the ninth identification information, the tenthidentification information, the seventeenth identification information,the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information at least.

The MME_A 40 receives the create session request message transmittedfrom the SGW_A 35. Furthermore, based on the reception of the createsession request message, the MME_A 40 acquires one or more pieces ofidentification information among the second identification information,the sixth identification information, the seventh identificationinformation, the eighth identification information, the ninthidentification information, the tenth identification information, theseventeenth identification information, the nineteenth identificationinformation, the twenty-first identification information, thetwenty-third identification information, the twenty-fifth identificationinformation, and the twenty-seventh identification information. Notethat the MME_A 40 may store the acquired identification information.

Next, in a case of the SCEF_A 46 initiated procedure, the SCEF_A 46performs a MME information acquisition procedure with the HSS_A 50(S2104). Based on the MME information acquisition procedure, the SCEF_A46 selects and/or determines the MME_A 40 to be used for establishmentof the PDU session and acquires information of the MME_A 40. Note thatthe SCEF_A 46 may select and/or determine the MME_A 40 to be used forestablishment of the PDU session in a method other than the MMEinformation acquisition procedure.

Based on the selection and/or determination of the MME_A 40 to be usedfor the establishment of the PDU session, the SCEF_A 46 transmits acreate session request message to the SGW_A 35 (S2106). The PGW_A 30 maytransmit, in the create session request message, one or more pieces ofidentification information among the second identification information,the sixth identification information, the seventh identificationinformation, the eighth identification information, the ninthidentification information, the tenth identification information, theseventeenth identification information, the nineteenth identificationinformation, the twenty-first identification information, thetwenty-third identification information, the twenty-fifth identificationinformation, and the twenty-seventh identification information at least.

The MME_A 40 receives the create session request message transmittedfrom the SCEF_A 46. Furthermore, based on the reception of the createsession request message, the MME_A 40 acquires one or more pieces ofidentification information among the second identification information,the sixth identification information, the seventh identificationinformation, the eighth identification information, the ninthidentification information, the tenth identification information, theseventeenth identification information, the nineteenth identificationinformation, the twenty-first identification information, thetwenty-third identification information, the twenty-fifth identificationinformation, and the twenty-seventh identification information. Notethat the MME_A 40 may store the acquired identification information.

Through the above steps, the procedure from S2100 to S2106 ends.

Next, the MME_A 40 selects an access network to be used for a PDUsession to be established (S2108). Note that the MME_A 40 may performselection of an access network, based on the reception of the createsession request message, or may perform selection of an access networkin a case of update of the operator policy or at any timing. For theselection of an access network, the MME_A 40 may use informationacquired from the UE_A 10 in a procedure, such as the attach procedure,may use the operator policy, or may use information stored in the MME_A40.

Based on the selection of an access network to be used for the PDUsession to be established, the MME_A 40 transmits a PDU sessionestablishment request message to the UE_A 10 (S2110). The MME_A 40 maytransmit, in the PDU session establishment request message, one or morepieces of identification information among the second identificationinformation, the sixth identification information, the seventhidentification information, the eighth identification information, theninth identification information, the tenth identification information,the seventeenth identification information, the nineteenthidentification information, the twenty-first identification information,the twenty-third identification information, the twenty-fifthidentification information, and the twenty-seventh identificationinformation at least.

The MME_A 40 and/or the core network_A 90 may indicate capability ofsupported Service Continuity by transmitting the PDU sessionestablishment request message including one or more pieces ofidentification information among the seventeenth identificationinformation, the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information. The MME_A 40 and/or the core network_A 90may request in more detail the type of PDU session to establish, bytransmitting the PDU session establishment request message including oneor more pieces of identification information among the sixthidentification information to the tenth identification information.

Note that the MME_A 40 may transmit the PDU session establishmentrequest message to an apparatus in the selected access network, and thetransmitted PDU session establishment request message may be transferredto the UE_A 10 via the apparatus in the access network. In this case,the apparatus in the access network may transmit the PDU sessionestablishment request message in an RRC message. Note that the RRCmessage may be an RRC connection reconfiguration request message.

The UE_A 10 receives the PDU session establishment request messagetransmitted from the MME_A 40 and/or the RRC message transmitted fromthe apparatus in the access network. Furthermore, based on the receptionof the PDU session establishment request message, the UE_A 10 acquiresone or more pieces of identification information among the secondidentification information, the sixth identification information, theseventh identification information, the eighth identificationinformation, the ninth identification information, the tenthidentification information, the seventeenth identification information,the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information. Note that the UE_A 10 may store the acquiredpieces of identification information.

Based on the reception of the PDU session establishment request messageand/or information included in the PDU session establishment requestmessage, the UE_A 10 may recognize the type of supported ServiceContinuity or may recognize that the PDU session has been established.

More specifically, the UE_A 10 may recognize that establishment of thefirst single-type PDU session is supported by a network, based on theseventeenth identification information, may recognize that establishmentof the second single-type PDU session is supported by a network, basedon the nineteenth identification information, or may recognize thatestablishment of the third single-type PDU session is supported by anetwork, based on the twenty-first identification information.

Furthermore, the UE_A 10 may recognize that establishment of the firstmulti-type PDU session is supported by a network, based on thetwenty-third identification information, may recognize thatestablishment of the second multi-type PDU session is supported by anetwork, based on the twenty-fifth identification information, or mayrecognize that establishment of the third multi-type PDU session issupported by a network, based on the twenty-seventh identificationinformation.

The UE_A 10 may recognize in more detail the type of PDU session to beestablished, based on one or more pieces of identification informationamong the sixth identification information to the tenth identificationinformation. For example, the UE_A 10 may recognize the IP addressallocated to the UE_A 10, based on the seventh identificationinformation.

The UE_A 10 may store one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information in association with the PDU session to beestablished. In other words, the PDU session to be established may beassociated with the one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information. For example, the PDU session to beestablished may be associated with the IP address allocated to the UE_A10.

Based on the reception of the PDU session establishment request message,the UE_A 10 transmits a PDU session establishment accept message to theMME_A 40 (S2112). The UE_A 10 may transmit, in the PDU sessionestablishment accept message, one or more pieces of identificationinformation among the eleventh identification information, the twelfthidentification information, the thirteenth identification information,the fourteenth identification information, the fifteenth identificationinformation, the sixteenth identification information, the eighteenthidentification information, the twentieth identification information,the twenty-second identification information, the twenty-fourthidentification information, and the twenty-sixth identificationinformation at least.

Note that the UE_A 10 may transmit the PDU session establishment acceptmessage to an apparatus in the access network, and the transmitted PDUsession establishment accept message may be transferred to the MME_A 40via the apparatus in the access network. In this case, the UE_A 10 maytransmit the PDU session establishment accept message in an RRC message.Note that the RRC message may be a direct transfer message.

Based on the reception of the RRC message, the UE_A 10 may transmit anRRC message to an apparatus in the access network, separately fromtransmission of the PDU session establishment accept message. In thiscase, the RRC message may be an RRC connection reconfiguration completemessage.

The MME_A 40 receives the PDU session establishment accept messagetransmitted from the UE_A 10. Furthermore, based on the reception of thePDU session establishment accept message, the MME_A 40 acquires one ormore pieces of identification information among the eleventhidentification information, the twelfth identification information, thethirteenth identification information, the fourteenth identificationinformation, the fifteenth identification information, the sixteenthidentification information, the eighteenth identification information,the twentieth identification information, the twenty-secondidentification information, the twenty-fourth identificationinformation, and the twenty-sixth identification information. Note thatthe MME_A 40 may store the acquired identification information.

Based on the reception of the PDU session establishment accept messageand/or information included in the PDU session establishment acceptmessage, the MME_A 40 may recognize the type of supported ServiceContinuity or may recognize that the PDU session has been established.

More specifically, the MME_A 40 may recognize that establishment of thefirst single-type PDU session is supported by the UE_A 10, based on thesixteenth identification information, may recognize that establishmentof the second single-type PDU session is supported by the UE_A 10, basedon the eighteenth identification information, or may recognize thatestablishment of the third single-type PDU session is supported by theUE_A 10, based on the twentieth identification information.

Furthermore, the MME_A 40 may recognize that establishment of the firstmulti-type PDU session is supported by the UE_A 10, based on thetwenty-second identification information, may recognize thatestablishment of the second multi-type PDU session is supported by theUE_A 10, based on the twenty-fourth identification information, or mayrecognize that establishment of the third multi-type PDU session issupported by the UE_A 10, based on the twenty-sixth identificationinformation.

The MME_A 40 may recognize in more detail the type of PDU session to beestablished, based on one or more pieces of identification informationamong the eleventh identification information to the fifteenthidentification information. For example, the MME_A 40 may recognize theIP address allocated to the UE_A 10, based on the twelfth identificationinformation.

The MME_A 40 may store one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information in association with the PDU session to beestablished. In other words, the PDU session to be established may beassociated with the one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information. For example, the PDU session to beestablished may be associated with the IP address allocated to the UE_A10.

Next, based on the reception of the PDU session establishment acceptmessage, the MME_A 40 transmits a create session response message.

In a case that the first network-initiated PDU session establishmentprocedure is under the initiative of the PGW_A 30, the MME_A 40transmits the create session response message to the SGW_A 35, based onthe reception of the PDU session establishment accept message (S2114).The MME_A 40 may transmit, in the create session response message, oneor more pieces of identification information among the eleventhidentification information, the twelfth identification information, thethirteenth identification information, the fourteenth identificationinformation, the fifteenth identification information, the sixteenthidentification information, the eighteenth identification information,the twentieth identification information, the twenty-secondidentification information, the twenty-fourth identificationinformation, and the twenty-sixth identification information at least.

The SGW_A 35 receives the create session response message transmittedfrom the MME_A 40. Furthermore, based on the reception of the createsession response message, the SGW_A 35 acquires one or more pieces ofidentification information among the eleventh identificationinformation, the twelfth identification information, the thirteenthidentification information, the fourteenth identification information,the fifteenth identification information, the sixteenth identificationinformation, the eighteenth identification information, the twentiethidentification information, the twenty-second identificationinformation, the twenty-fourth identification information, and thetwenty-sixth identification information. Note that the SGW_A 35 maystore the acquired identification information.

Based on the reception of the create session response message, the SGW_A35 transmits the create session response message to the PGW_A 30(S2116). The SGW_A 35 may transmit, in the create session responsemessage, one or more pieces of identification information among theeleventh identification information, the twelfth identificationinformation, the thirteenth identification information, the fourteenthidentification information, the fifteenth identification information,the sixteenth identification information, the eighteenth identificationinformation, the twentieth identification information, the twenty-secondidentification information, the twenty-fourth identificationinformation, and the twenty-sixth identification information at least.

The PGW_A 30 receives the create session response message transmittedfrom the SGW_A 35. Furthermore, based on the reception of the createsession response message, the PGW_A 30 acquires one or more pieces ofidentification information among the eleventh identificationinformation, the twelfth identification information, the thirteenthidentification information, the fourteenth identification information,the fifteenth identification information, the sixteenth identificationinformation, the eighteenth identification information, the twentiethidentification information, the twenty-second identificationinformation, the twenty-fourth identification information, and thetwenty-sixth identification information. Note that the PGW_A 30 maystore the acquired identification information.

In a case that the first network-initiated PDU session establishmentprocedure is under the initiative of the SCEF_A 46, the MME_A 40transmits a create session response message to the SCEF_A 46, based onthe reception of the PDU session establishment accept message. (S2118).The MME_A 40 may transmit, in the create session response message, oneor more pieces of identification information among the eleventhidentification information, the twelfth identification information, thethirteenth identification information, the fourteenth identificationinformation, the fifteenth identification information, the sixteenthidentification information, the eighteenth identification information,the twentieth identification information, the twenty-secondidentification information, the twenty-fourth identificationinformation, and the twenty-sixth identification information at least.

The SCEF_A 46 receives the create session response message transmittedfrom the MME_A 40. Furthermore, based on the reception of the createsession response message, the SCEF_A 46 acquires one or more pieces ofidentification information among the eleventh identificationinformation, the twelfth identification information, the thirteenthidentification information, the fourteenth identification information,the fifteenth identification information, the sixteenth identificationinformation, the eighteenth identification information, the twentiethidentification information, the twenty-second identificationinformation, the twenty-fourth identification information, and thetwenty-sixth identification information. Note that the SCEF_A 46 maystore the acquired identification information.

Moreover, in a case that the first network-initiated PDU sessionestablishment procedure is under the initiative of the MME_A 40, theprocedure from S2114 to S2118 may be omitted.

Through the above steps, the first network-initiated PDU sessionestablishment procedure is completed. With the completion of the firstnetwork-initiated PDU session establishment procedure, the UE_A 10and/or the core network_A 90 can establish the PDU session. Moreover,with the completion of the first network-initiated PDU sessionestablishment procedure, the UE_A 10 and/or the core network_A 90 canrecognize and store the type of supported Service Continuity.

Specifically, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may recognize that establishment ofthe first single-type PDU session is supported, based on the sixteenthidentification information and/or the seventeenth identificationinformation, may recognize that establishment of the second single-typePDU session is supported, based on the eighteenth identificationinformation and/or the nineteenth identification information, or mayrecognize that establishment of the third single-type PDU session issupported, based on the twentieth identification information and/or thetwenty-first identification information.

Furthermore, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may recognize that establishment ofthe first multi-type PDU session is supported, based on thetwenty-second identification information and/or the twenty-thirdidentification information, may recognize that establishment of thesecond multi-type PDU session is supported, based on the twenty-fourthidentification information and/or the twenty-fifth identificationinformation, or may recognize that establishment of the third multi-typePDU session is supported, based on the twenty-sixth identificationinformation and/or the twenty-seventh identification information.

1.3.2.2.2. Example of Second Network-Initiated PDU Session EstablishmentProcedure

Next, an example of the steps of the second network-initiated PDUsession establishment procedure will be described with reference to FIG.22. The second network-initiated PDU session establishment procedure isa procedure in which the UE_A 10 selects an access network to be usedfor establishment of a PDU session to establish a PDU session betweenthe UE_A 10 and the core network_A 90.

The second network-initiated PDU session establishment procedureincludes a PGW_A 30 initiated procedure, a SCEF_A 46 initiatedprocedure, and a MME_A 40 initiated procedure. Note that the procedurein S2200 to S2202 is performed in the PGW_A 30 initiated procedure,while the procedure in S2204 to S2206 is performed in the SCEF_A 46initiated procedure. Moreover, in the MME_A 40 initiated procedure, theprocedure is started from S2108 without performing the procedure inS2200 to S2206. Alternatively, the MME_A 40 may transmit a controlmessage for creating a session under the initiative of a network to thePGW_A 30, and the PGW_A may start the PGW_A 30 initiated procedure,based on the reception of the control message transmitted from the MME_A40. Similarly, the MME_A 40 may transmit a control message for creatinga session under the initiative of a network to the SCEF_A 46, and theSCEF_A 46 may start the SCEF_A 46 initiated procedure, based on thereception of the control message transmitted from the MME_A 40. In thiscase, the MME_A 40 may perform a process of selecting an access network(S2108) before the transmission of the control message. Note that theMME_A 40 may transmit, in the control message, one or more pieces ofidentification information among the second identification information,the sixth identification information, the seventh identificationinformation, the eighth identification information, the ninthidentification information, the tenth identification information, theseventeenth identification information, the nineteenth identificationinformation, the twenty-first identification information, thetwenty-third identification information, the twenty-fifth identificationinformation, and the twenty-seventh identification information at least.

Note that the procedure from S2200 to S2206 may be the same as theprocedure from S2100 to S2106 in the first network-initiated PDU sessionestablishment procedure. Therefore, description of the steps will beomitted.

Next, the MME_A 40 transmits a first PDU session establishment requestmessage to the UE_A 10 (S2208). The MME_A 40 may transmit, in the firstPDU session establishment request message, one or more pieces ofidentification information among the second identification information,the sixth identification information, the seventh identificationinformation, the eighth identification information, the ninthidentification information, the tenth identification information, theseventeenth identification information, the nineteenth identificationinformation, the twenty-first identification information, thetwenty-third identification information, the twenty-fifth identificationinformation, and the twenty-seventh identification information at least.

The MME_A 40 and/or the core network_A 90 may indicate capability ofsupported Service Continuity by transmitting the first PDU sessionestablishment request message including one or more pieces ofidentification information among the seventeenth identificationinformation, the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information. The MME_A 40 and/or the core network_A 90may request in more detail the type of PDU session to establish, bytransmitting the first PDU session establishment request messageincluding one or more pieces of identification information among thesixth identification information to the tenth identificationinformation.

Note that the MME_A 40 may transmit the first PDU session establishmentrequest message to an apparatus in the access network_A, and thetransmitted first PDU session establishment request message may betransferred to the UE_A 10 via the apparatus in the access network_A. Inthis case, the apparatus in the access network_A may transmit the firstPDU session establishment request message in an RRC message. Note thatthe RRC message may be a direct transfer message.

Here, the access network used to transmit the first PDU sessionestablishment request message is defined as the access network_A. Theaccess network_A may be an access network selected by the MME_A 40 ormay be an access network selected by another apparatus.

The UE_A 10 receives the first PDU session establishment request messagetransmitted from the MME_A 40 and/or the RRC message transmitted from anapparatus in the access network. Furthermore, based on the reception ofthe first PDU session establishment request message, the UE_A 10acquires one or more pieces of identification information among thesecond identification information, the sixth identification information,the seventh identification information, the eighth identificationinformation, the ninth identification information, the tenthidentification information, the seventeenth identification information,the nineteenth identification information, the twenty-firstidentification information, the twenty-third identification information,the twenty-fifth identification information, and the twenty-seventhidentification information. Note that the UE_A 10 may store the acquiredpieces of identification information.

Based on the reception of the first PDU session establishment requestmessage, the UE_A 10 selects an access network to be used for the PDUsession to be established (S2210). Note that, for the selection of anaccess network, the UE_A 10 may use information received in the firstPDU session establishment request message, may use information acquiredfrom the network in the attach procedure, may use information acquiredfrom the network outside the attach procedure, or may use informationstored in the UE_A 10.

Here, the access network used in the PDU session to be established isdefined as an access network B. The access network B may be the sameaccess network as the access network_A or may be an access networkdifferent from the access network_A. Furthermore, the access network Bmay be an access network selected by the UE_A 10 or may be an accessnetwork selected by another apparatus.

In other words, based on the reception of the first PDU sessionestablishment request message, the UE_A 10 may not necessarily select anaccess network to use in the PDU session to establish.

Based on the reception of the first PDU session establishment requestmessage and/or information included in the first PDU sessionestablishment request message, the UE_A 10 may recognize the type ofsupported Service Continuity or may recognize that the PDU session hasbeen established.

More specifically, the UE_A 10 may recognize that establishment of thefirst single-type PDU session is supported by a network, based on theseventeenth identification information, may recognize that establishmentof the second single-type PDU session is supported by a network, basedon the nineteenth identification information, or may recognize thatestablishment of the third single-type PDU session is supported by anetwork, based on the twenty-first identification information.

Furthermore, the UE_A 10 may recognize that establishment of the firstmulti-type PDU session is supported by a network, based on thetwenty-third identification information, may recognize thatestablishment of the second multi-type PDU session is supported by anetwork, based on the twenty-fifth identification information, or mayrecognize that establishment of the third multi-type PDU session issupported by a network, based on the twenty-seventh identificationinformation.

The UE_A 10 may recognize in more detail the type of PDU session to beestablished, based on one or more pieces of identification informationamong the sixth identification information to the tenth identificationinformation. For example, the UE_A 10 may recognize the IP addressallocated to the UE_A 10, based on the seventh identificationinformation.

The UE_A 10 may store one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information in association with the PDU session to beestablished. In other words, the PDU session to be established may beassociated with the one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information. For example, the PDU session to beestablished may be associated with the IP address allocated to the UE_A10.

Based on the reception of the PDU session establishment request messageand/or the selection of an access network, the UE_A 10 transmits asecond PDU session establishment request message to the MME_A 40(S2212). The UE_A 10 may transmit, in the second PDU sessionestablishment request message, one or more pieces of identificationinformation among the eleventh identification information, the twelfthidentification information, the thirteenth identification information,the fourteenth identification information, the fifteenth identificationinformation, the sixteenth identification information, the eighteenthidentification information, the twentieth identification information,the twenty-second identification information, the twenty-fourthidentification information, and the twenty-sixth identificationinformation at least.

Note that the UE_A 10 may transmit the second PDU session establishmentrequest message to an apparatus in the access network B, and thetransmitted second PDU session establishment request message may betransferred to the MME_A 40 via the apparatus in the access network B.In this case, the UE_A 10 may transmit the second PDU sessionestablishment request message in an RRC message.

Furthermore, the UE_A 10 may transmit, or may not necessarily transmit,a response message to the first PDU session establishment requestmessage to the MME_A 40, separately from the second PDU establishmentrequest message. The MME_A 40 may receive, or may not necessarilytransmit, the response message to the first PDU session establishmentrequest message transmitted from the UE_A 10. Note that the UE_A 10 maytransmit the response message to the first PDU session establishmentrequest message to an apparatus in the access network_A, and thetransmitted response message to the first PDU session establishmentrequest message may be transferred to the MME_A 40 via the apparatus inthe access network_A.

The MME_A 40 receives the second PDU session establishment requestmessage transmitted from the UE_A 10. Furthermore, based on thereception of the second PDU session establishment request message, theMME_A 40 acquires one or more pieces of identification information amongthe eleventh identification information, the twelfth identificationinformation, the thirteenth identification information, the fourteenthidentification information, the fifteenth identification information,the sixteenth identification information, the eighteenth identificationinformation, the twentieth identification information, the twenty-secondidentification information, the twenty-fourth identificationinformation, and the twenty-sixth identification information. Note thatthe MME_A 40 may store the acquired identification information.

Based on the reception of the second PDU session establishment requestmessage and/or information included in the second PDU sessionestablishment request message, the MME_A 40 may recognize the type ofsupported Service Continuity or may recognize that the PDU session hasbeen established.

More specifically, the MME_A 40 may recognize that establishment of thefirst single-type PDU session is supported by the UE_A 10, based on thesixteenth identification information, may recognize that establishmentof the second single-type PDU session is supported by the UE_A 10, basedon the eighteenth identification information, or may recognize thatestablishment of the third single-type PDU session is supported by theUE_A 10, based on the twentieth identification information.

Furthermore, the MME_A 40 may recognize that establishment of the firstmulti-type PDU session is supported by the UE_A 10, based on thetwenty-second identification information, may recognize thatestablishment of the second multi-type PDU session is supported by theUE_A 10, based on the twenty-fourth identification information, or mayrecognize that establishment of the third multi-type PDU session issupported by the UE_A 10, based on the twenty-sixth identificationinformation.

The MME_A 40 may recognize in more detail the type of PDU session to beestablished, based on one or more pieces of identification informationamong the eleventh identification information to the fifteenthidentification information. For example, the MME_A 40 may recognize theIP address allocated to the UE_A 10, based on the twelfth identificationinformation.

The MME_A 40 may store one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information in association with the PDU session to beestablished. In other words, the PDU session to be established may beassociated with the one or more pieces of identification informationamong the sixth identification information to the fifteenthidentification information. For example, the PDU session to beestablished may be associated with the IP address allocated to the UE_A10.

Next, based on the reception of the second PDU session establishmentrequest message, the MME_A 40 transmits a create session responsemessage.

In a case that the second network-initiated PDU session establishmentprocedure is under the initiative of the PGW_A 30, the procedure fromS2214 to S2216 is performed; in a case that the second network-initiatedPDU session establishment procedure is a SCEF_A 46 initiated procedure,the procedure to S2218 is performed.

Note that the procedure from S2214 to S2218 may be the same as theprocedure from S2114 to S2118 in the first network-initiated PDU sessionestablishment procedure. Therefore, description of the steps will beomitted.

Based on the reception of the second PDU session establishment requestmessage and/or the transmission of the create session response message,the MME_A 40 transmits a PDU session establishment accept message to theUE_A 10 (S2220).

Note that the MME_A 40 may transmit the PDU session establishment acceptmessage to an apparatus in the access network B, and the transmitted PDUsession establishment accept message may be transferred to the UE_A 10via the apparatus in the access network B. In this case, the apparatusin the access network B may transmit the PDU session establishmentaccept message in an RRC message.

The UE_A 10 receives the PDU session establishment accept messagetransmitted from the MME_A 40 and/or the RRC message transmitted fromthe apparatus in the access network.

The UE_A 10 may transmit a PDU session establishment complete message tothe MME_A 40, based on the reception of the PDU session establishmentaccept message, or may transmit an RRC message to an apparatus in theaccess network B, based on the reception of the RRC message.

Through the above steps, the second network-initiated PDU sessionestablishment procedure is completed. With the completion of the secondnetwork-initiated PDU session establishment procedure, the UE_A 10and/or the core network_A 90 can establish the PDU session. Moreover,with the completion of the second network-initiated PDU sessionestablishment procedure, the UE_A 10 and/or the core network_A 90 canrecognize and store the type of supported Service Continuity.

Specifically, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may recognize that establishment ofthe first single-type PDU session is supported, based on the sixteenthidentification information and/or the seventeenth identificationinformation, may recognize that establishment of the second single-typePDU session is supported, based on the eighteenth identificationinformation and/or the nineteenth identification information, or mayrecognize that establishment of the third single-type PDU session issupported, based on the twentieth identification information and/or thetwenty-first identification information.

Furthermore, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may recognize that establishment ofthe first multi-type PDU session is supported, based on thetwenty-second identification information and/or the twenty-thirdidentification information, may recognize that establishment of thesecond multi-type PDU session is supported, based on the twenty-fourthidentification information and/or the twenty-fifth identificationinformation, or may recognize that establishment of the third multi-typePDU session is supported, based on the twenty-sixth identificationinformation and/or the twenty-seventh identification information.

1.3.3. Example of Flow Switching Procedure

Next, an example of a flow switching procedure will be described.

The flow switching procedure is a procedure in which the UE_A 10 and/orthe core network_A 90 switches a PDU session to be used for transmissionand/or reception of user data. The UE_A 10 and/or the MME_A 40 and/orthe SGW_A 35 and/or the PGW_A 30 and/or the SCEF_A 46 can switch a PDUsession to be used for transmission and/or reception of user data,through the flow switching procedure. Note that the granularity of userdata for switching a PDU session may be a unit of packet, a unit offlow, or a unit of application. The granularity of user data forswitching a PDU session is not limited to these. The flow switchingprocedure may be performed at any timing as long as being performedafter multiple PDU sessions are established.

The flow switching procedure includes a UE-initiated flow switchingprocedure, which is started under the initiative of the UE_A 10, and anetwork-initiated flow switching procedure.

1.3.3.1. Example of UE-Initiated Flow Switching Procedure

Next, an example of the steps of the UE-initiated flow switchingprocedure will be described. The UE-initiated flow switching procedureis a procedure for switching a PDU session to be used for transmissionand/or reception of user data, under the initiative of the UE.

The example of the steps of the UE-initiated flow switching procedurewill be described with reference to FIG. 23.

The UE_A 10 transmits a flow change request message to the MME_A 40 viathe selected access network (S2300). Note that the UE_A 10 may transmitthe flow change request message to an apparatus in the access network,and the transmitted flow change request message may be transferred tothe MME_A 40 via the apparatus in the selected access network. The UE_A10 may transmit the forty-fourth identification information in the flowchange request message.

The MME_A 40 receives the flow change request message transmitted fromthe UE_A 10. Furthermore, the MME_A 40 may acquire the forty-fourthidentification information, based on the reception of the flow changerequest message. Note that the MME_A 40 may store the acquiredidentification information.

The MME_A 40 may identify the switching source PDU session or mayidentify the switching destination PDU session, based on the receptionof the flow change message and/or the forty-fourth identificationinformation.

The MME_A 40 transmits a resource change request message to theapparatus, with which the switching source and/or switching destinationPDU session is established, based on the reception of the flow changemessage and/or the forty-fourth identification information.

Specifically, in a case that the apparatus with which the switchingsource and/or switching destination PDU session is established is theSGW_A 35 and/or the PGW_A 30, the MME_A 40 transmits the resource changerequest message to the SGW_A 35 (S2302). Moreover, in a case that theapparatus with which the switching source and/or switching destinationPDU session is established is the SCEF_A 46, the MME_A 40 transmits theresource change request message to the SCEF_A 46 (S2306). Note thatMME_A 40 may transmit at least the forty-fourth identificationinformation and/or the forty-fifth identification information in theresource change request message.

The SGW_A 35 and/or the SCEF_A 46 receives the resource change requestmessage transmitted from the MME_A 40. Furthermore, the SGW_A 35 and/orthe SCEF_A 46 may acquire the forty-fourth identification informationand/or the forty-fifth identification information, based on thereception of the resource change request message. Note that the SGW_A 35and/or the SCEF_A 46 may store the acquired identification information.

Note that, in a case that the SGW_A 35 has received the resource changerequest message, the SGW_A 35 transmits the resource change requestmessage to the PGW_A 30 (S2306). Note that SGW_A 35 may transmit atleast the forty-fourth identification information and/or the forty-fifthidentification information in the resource change request message.

The PGW_A 30 receives the resource change request message transmittedfrom the SGW_A 35. Furthermore, the PGW_A 30 may acquire theforty-fourth identification information and/or the forty-fifthidentification information, based on the reception of the resourcechange request message. Note that the PGW_A 30 may store the acquiredidentification information.

The PGW_A 30 and/or the SCEF_A 46 performs a network-initiated flowswitching procedure that will be described later, based on the receptionof the resource change request message (S2308). Specifically, the PGW_A30 may perform the network-initiated flow switching procedure under theinitiative of the PGW_A 30 in a case that the PGW_A 30 has received theresource change request message, and the SCEF_A 46 may perform thenetwork-initiated flow switching procedure under the initiative of theSCEF_A 46 in a case that the SCEF_A 46 has received the resource changerequest message.

In a case that the network-initiated flow switching procedure isperformed in the UE-initiated session establishment procedure, thesession modification request message may be a response message to theresource change request message, and the PDU session modificationrequest message may be a flow change request message. Moreover, theforty-sixth identification information included in the sessionmodification request message and/or the PDU session modification requestmessage may be the forty-fifth identification information.

Through the above steps, the UE-initiated flow switching procedure iscompleted. With the completion of the UE-initiated flow switchingprocedure, the UE_A 10 and/or the core network_A 90 can switch a PDUsession to be used for transmission and/or reception of user data.

Specifically, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may identify the switching sourceand/or switching destination PDU session, may switch a PDU session to beused for transmission and/or reception of user data, or may recognizethat a PDU session to be used for transmission and/or reception of userdata has been switched, based on the forty-fourth identificationinformation and/or the forty-fifth identification information.

Furthermore, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may maintain, instead of releasing,the switching source PDU session, based on the forty-fourthidentification information and/or the forty-fifth identificationinformation.

1.3.3.2. Example of Network-Initiated Flow Switching Procedure

Next, an example of steps of the network-initiated flow switchingprocedure will be described. The network-initiated flow switchingprocedure is a procedure for switching a PDU session to be used fortransmission and/or reception of user data under the initiative of thePGW_A 30 and/or the SCEF_A 46.

The example of the steps of the network-initiated flow switchingprocedure will be described with reference to FIG. 24.

The network-initiated flow switching procedure includes a PGW_A 30initiated procedure and a SCEF_A 46 initiated procedure. Note that theprocedure in S2400 to S2402 is performed in the PGW_A 30 initiatedprocedure, while the procedure of S2404 is performed in the SCEF_A 46initiated procedure. Alternatively, in the MME_A 40 initiated procedure,the MME_A 40 may transmit a control message for switching the flow underthe initiative of a network to the PGW_A 30, and the PGW_A may start thePGW_A 30 initiated procedure, based on the reception of the controlmessage transmitted from the MME_A 40. Similarly, the MME_A 40 maytransmit a control message for switching the flow under the initiativeof a network to the SCEF_A 46, and the SCEF_A 46 may start the SCEF_A 46initiated procedure, based on the reception of the control messagetransmitted from the MME_A 40. Note that the MME_A 40 may transmit atleast the forty-sixth identification information in the control message.

First, a description will be given of the steps of the procedure fromS2400 to S2404.

In a case of the PGW_A 30 initiated procedure, the PGW_A 30 transmits asession modification request message to the SGW_A 35 (S2400). The PGW_A30 may transmit at least the forty-sixth identification information inthe session modification request message.

The SGW_A 35 receives the session modification request messagetransmitted from the PGW_A 30. Furthermore, the SGW_A 35 acquires theforty-sixth identification information, based on the reception of thesession modification request message. Note that the SGW_A 35 may storethe acquired identification information.

The SGW_A 35 transmits the session modification request message to theMME_A 40 (S2402). The SGW_A 35 may transmit at least the forty-sixthidentification information in the session modification request message.

The MME_A 40 receives the session modification request messagetransmitted from the SGW_A 35. Furthermore, the MME_A 40 acquires theforty-sixth identification information, based on the reception of thesession modification request message. Note that the MME_A 40 may storethe acquired identification information.

Next, in a case of the SCEF_A 46 initiated procedure, the CEF_A 46transmits a session modification request message to the SGW_A 35(S2404). The PGW_A 30 may transmit at least the forty-sixthidentification information in the session modification request message.

The MME_A 40 receives the session modification request messagetransmitted from the SCEF_A 46. Furthermore, the MME_A 40 acquires theforty-sixth identification information, based on the reception of thesession modification request message. Note that the MME_A 40 may storethe acquired identification information.

Through the above steps, the procedure from S2400 to S2404 ends.

Next, the MME_A 40 transmits a PDU session modification request messageto the UE_A 10, based on the reception of the session modificationrequest message (S2406). The MME_A 40 may transmit at least theforty-sixth identification information in the PDU session modificationrequest message.

Note that the MME_A 40 may transmit the PDU session modification requestmessage to an apparatus in the access network, and the transmitted PDUsession modification request message may be transferred to the UE_A 10via the apparatus in the access network. In this case, the apparatus inthe access network may transmit the PDU session modification requestmessage in an RRC message. Note that the RRC message may be an RRCconnection reconfiguration request message or a direct transfer message.

The UE_A 10 receives the PDU session modification request messagetransmitted from the MME_A 40 and/or the RRC message transmitted fromthe apparatus in the access network. Furthermore, the UE_A 10 acquiresthe forty-sixth identification information, based on the reception ofthe PDU session modification request message. Note that the UE_A 10 maystore the acquired pieces of identification information.

The UE_A 10 may identify the switching source PDU session or mayidentify the switching destination PDU session, based on the receptionof the PDU session modification request message and/or the forty-sixthidentification information.

Based on the reception of the PDU session modification request message,the UE_A 10 transmits a PDU session modification accept message to theMME_A 40 (S2408). The UE_A 10 may transmit at least the forty-seventhidentification information in the PDU session modification acceptmessage.

Note that the UE_A 10 may transmit the PDU session modification acceptmessage to an apparatus in the access network, and the transmitted PDUsession modification accept message may be transferred to the MME_A 40via the apparatus in the access network. In this case, the UE_A 10 maytransmit the PDU session modification accept message in an RRC message.Note that the RRC message may be a direct transfer message.

Based on the reception of the RRC message, the UE_A 10 may transmit anRRC message to an apparatus in the access network, separately fromtransmission of the PDU session modification accept message. In thiscase, the RRC message may be an RRC connection reconfiguration completemessage.

The MME_A 40 receives the PDU session modification accept messagetransmitted from the UE_A 10. Furthermore, the MME_A 40 acquires theforty-seventh identification information, based on the reception of thePDU session modification accept message. Note that the MME_A 40 maystore the acquired identification information.

The MME_A 40 may recognize that the switching of the PDU session to beused for transmission and/or reception of user data is allowed, based onthe reception of the PDU session modification accept message and/or theforty-seventh identification information. The MME_A 40 may identify theswitching source PDU session or may identify the switching destinationPDU session, based on the forty-seventh identification information.

Next, based on the reception of the PDU session modification acceptmessage, the MME_A 40 transmits a session modification response message.

In a case that the network-initiated flow switching procedure is underthe initiative of the PGW_A 30, the MME_A 40 transmits the sessionmodification response message to the SGW_A 35, based on the reception ofthe PDU session modification accept message (S2410). The MME_A 40 maytransmit at least the forty-seventh identification information in thesession modification response message.

The SGW_A 35 receives the session modification response messagetransmitted from the MME_A 40. Furthermore, the SGW_A 35 acquires theforty-seventh identification information, based on the reception of thesession modification response message. Note that the SGW_A 35 may storethe acquired identification information.

Based on the reception of the session modification response message, theSGW_A 35 transmits the session modification response message to thePGW_A 30 (S2412). The SGW_A 35 may transmit at least the forty-seventhidentification information in the session modification response message.

The PGW_A 30 receives the session modification response messagetransmitted from the SGW_A 35. Furthermore, the PGW_A 30 acquires theforty-seventh identification information, based on the reception of thesession modification response message. Note that the PGW_A 30 may storethe acquired identification information.

In a case that the network-initiated flow switching procedure is underthe initiative of the SCEF_A 46, the MME_A 40 transmits the sessionmodification response message to the SCEF_A 46, based on the receptionof the PDU session modification accept message. (S2414). The MME_A 40may transmit at least the forty-seventh identification information inthe session modification response message.

The SCEF_A 46 receives the session modification response messagetransmitted from the MME_A 40. Furthermore, the SCEF_A 46 acquires theforty-seventh identification information, based on the reception of thesession modification response message. Note that the SCEF_A 46 may storethe acquired identification information.

Through the above steps, the network-initiated flow switching procedureis completed. With the completion of the network-initiated flowswitching procedure, the UE_A 10 and/or the core network_A 90 can switcha PDU session to be used for transmission and/or reception of user data.

Specifically, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may identify the switching sourceand/or switching destination PDU session, may switch a PDU session to beused for transmission and/or reception of user data, or may recognizethat a PDU session to be used for transmission and/or reception of userdata has been switched, based on the forty-sixth identificationinformation and/or the forty-seventh identification information.

Furthermore, the UE_A 10 and/or the MME_A 40 and/or the SGW_A 35 and/orthe PGW_A 30 and/or the SCEF_A 46 may maintain, instead of releasing,the switching source PDU session, based on the forty-sixthidentification information and/or the forty-seventh identificationinformation.

1.3.3. Modified Example of the Present Embodiment

Each of the apparatuses in the present embodiment may be an apparatusdifferent from the corresponding apparatus described above.

For example, the MME_A 40 is an apparatus playing a role in mobilitymanagement of each apparatus such as the UE_A 10 and/or sessionmanagement between apparatuses. However, in the core network_A 90 in thepresent embodiment, the role for mobility management and the role forsession management may be played by different apparatuses.

Specifically, a Session Management Entity (SME) may perform a functionof session management in the MME_A 40. In this case, the MME_A 40 in thepresent embodiment may be replaced with a Session Management Entity(SME). Furthermore, each message transmitted from and/or received by theMME_A 40 described in the communication procedure in the presentembodiment may be transmitted from and/or received by the SME, and eachprocess performed by the MME_A 40 may be performed by the SME.

2. Modified Example

A program running on an apparatus according to the present invention mayserve as a program that controls a Central Processing Unit (CPU) and thelike to cause a computer to operate in such a manner as to realize thefunctions of the embodiments according to the present invention.Programs or the information handled by the programs are temporarilystored into a volatile memory, such as a Random Access Memory (RAM), orstored in a non-volatile memory, such as a flash memory, a Hard DiskDrive (HDD), or another storage device system.

Note that programs for implementing the functions of the embodimentsrelating to the present invention may be recorded on a computer-readablerecording medium. This configuration may be realized by causing acomputer system to read the program recorded on this recording mediumfor execution. It is assumed that the “computer system” refers to acomputer system built into the apparatuses, and the computer systemincludes an operating system and hardware components such as aperipheral device. Furthermore, the “computer-readable recording medium”may be any of a semiconductor recording medium, an optical recordingmedium, a magnetic recording medium, a medium dynamically holding aprogram for a short time period, or another computer-readable recordingmedium.

Furthermore, each functional block or various characteristics of theapparatuses used in the above-described embodiments may be implementedor performed on an electric circuit, that is, an integrated circuit ormultiple integrated circuits, for example. An electric circuit designedto perform the functions described in the present specification mayinclude a general-purpose processor, a Digital Signal Processor (DSP),an Application Specific Integrated Circuit (ASIC), a Field ProgrammableGate Array (FPGA), or other programmable logic devices, discrete gatesor transistor logic, discrete hardware components, or a combinationthereof. The general-purpose processor may be a microprocessor, or theprocessor may be a processor of known type, a controller, amicro-controller, or a state machine. The above-mentioned electriccircuits may be constituted of a digital circuit, or may be constitutedof an analog circuit. Furthermore, in a case that with advances insemiconductor technology, a circuit integration technology appears thatreplaces the present integrated circuits, it is also possible for thepresent invention to use a new integrated circuit based on thetechnology.

Note that the invention of the present patent application is not limitedto the above-described embodiments. In the embodiments, apparatuses havebeen described as an example, but the invention of the presentapplication is not limited to these apparatuses, and is applicable to aterminal apparatus or a communication apparatus of a fixed-type or astationary-type electronic apparatus installed indoors or outdoors, forexample, an AV apparatus, a kitchen apparatus, a cleaning or washingmachine, an air-conditioning apparatus, office equipment, a vendingmachine, and other household apparatuses.

The embodiments of the present invention have been described in detailabove referring to the drawings, but the specific configuration is notlimited to the embodiments and includes, for example, an amendment to adesign that falls within the scope that does not depart from the gist ofthe present invention. Furthermore, various modifications are possiblewithin the scope of the present invention defined by claims, andembodiments that are made by suitably combining technical meansdisclosed according to the different embodiments are also included inthe technical scope of the present invention. Furthermore, aconfiguration in which a constituent element that achieves the sameeffect is substituted for the one that is described in the embodimentsis also included in the technical scope of the present invention.

REFERENCE SIGNS LIST

-   1 Communication system-   5 PDN_A-   10 UE_A-   20 UTRAN_A-   22 eNB (UTRAN)_A-   24 RNC_A-   25 GERAN_A-   26 BSS_A-   30 PGW_A-   35 SGW_A-   40 MME_A-   45 eNB_A-   46 SCEF_A-   50 HSS_A-   55 AAA_A-   60 PCRF_A-   65 ePDG_A-   70 WLAN ANa-   72 WLAN APa-   74 TWAG_A-   75 WLAN ANb-   76 WLAN APb-   80 LTE AN_A-   90 Core network_A-   120 5G RAN-   122 5GBS_A-   125 WLAN ANc-   126 WAG_A

The invention claimed is:
 1. A User Equipment (UE) comprising: acontroller; and transmission and reception circuitry, wherein in a firstprocedure for releasing a first Protocol Data Unit (PDU) session after asecond PDU session has been established, the controller is configuredfor initiating a UE requested PDU session establishment procedure usingat least first identification information and second identificationinformation in a case of establishing the second PDU session, the firstidentification information is a PDU session type that the UE provided ina UE requested PDU session establishment procedure for establishing thefirst PDU session, and the second identification information isinformation identifying a Data Network (DN).
 2. The UE according toclaim 1, wherein the transmission and reception circuitry is furtherconfigured for receiving information identifying the first PDU sessionfrom a core network in the first procedure.
 3. The UE according to claim1, wherein the transmission and reception circuitry is able to switch aflow from the first PDU session to the second PDU session after thesecond PDU session has been established.
 4. The UE according to claim 1,wherein the second identification information is the same as informationindicating the DN, the information having been transmitted from the UEfor establishing the first PDU session.
 5. The UE according to claim 1,wherein the second identification information is equivalent to an AccessPoint Name (APN).
 6. The UE according to claim 1, wherein thetransmission and reception circuitry is able to perform transmitting andreceiving of user data by using the second PDU session after the secondPDU session is established.
 7. A core network device wherein in a firstprocedure for releasing a first Protocol Data Unit (PDU) session after asecond PDU session has been established, the core network deviceperforms a User Equipment (UE) requested PDU session establishmentprocedure using at least first identification information and secondidentification information in a case of establishing the second PDUsession, the first identification information is a PDU session type thatwas provided in a UE requested PDU session establishment procedure forestablishing the first PDU session, and the second identificationinformation is information identifying a Data Network (DN).
 8. The corenetwork device according to claim 7, wherein the core network devicefurther transmits information identifying the first PDU session to theUE in the first procedure.
 9. The core network device according to claim7, wherein the core network device is able to switch a flow from thefirst PDU session to the second PDU session after the second PDU sessionhas been established.
 10. The core network device according to claim 7,wherein the second identification information is the same as informationindicating the DN, the information having been received from the UE forestablishing the first PDU session.
 11. The core network deviceaccording to claim 7, wherein the second identification information isequivalent to an Access Point Name (APN).
 12. The core network deviceaccording to claim 7, wherein the core network device is able to performtransmitting and receiving of user data by using the second PDU sessionafter the second PDU session is established.
 13. A communication controlmethod performed by a User Equipment (UE), the communication controlmethod comprising: in a first procedure for releasing a first ProtocolData Unit (PDU) session after a second PDU session has been established,initiating a UE requested PDU session establishment procedure using atleast first identification information and second identificationinformation in a case of establishing the second PDU session, whereinthe first identification information is a PDU session type that the UEprovided in a UE requested PDU session establishment procedure forestablishing the first PDU session, and the second identificationinformation is information identifying a Data Network (DN).
 14. Thecommunication control method performed by the UE according to claim 13,the communication control method further comprising: receivinginformation identifying the first PDU session from a core network in thefirst procedure.
 15. The communication control method performed by theUE according to claim 13, wherein the UE is able to switch a flow fromthe first PDU session to the second PDU session after the second PDUsession has been established.
 16. The communication control methodperformed by the UE according to claim 13, wherein the secondidentification information is the same as information indicating the DN,the information having been transmitted from the UE for establishing thefirst PDU session.
 17. The communication control method performed by theUE according to claim 13, wherein the second identification informationis equivalent to an Access Point Name (APN).
 18. The communicationcontrol method performed by the UE according to claim 13, wherein the UEis able to perform transmitting and receiving of user data by using thesecond PDU session after the second PDU session is established.
 19. Acommunication control method performed by a core network device, thecommunication control method comprising: in a first procedure forreleasing a first Protocol Data Unit (PDU) session after a second PDUsession has been established, performing a User Equipment (UE) requestedPDU session establishment procedure using at least first identificationinformation and second identification information in a case ofestablishing the second PDU session, wherein the first identificationinformation is a PDU session type that was provided in a UE requestedPDU session establishment procedure for establishing the first PDUsession, and the second identification information is informationidentifying a Data Network (DN).
 20. The communication control methodperformed by the core network device according to claim 19, thecommunication control method further comprising: transmittinginformation identifying the first PDU session to the UE in the firstprocedure.
 21. The communication control method performed by the corenetwork device according to claim 19, wherein the core network device isable to switch a flow from the first PDU session to the second PDUsession after the second PDU session has been established.
 22. Thecommunication control method performed by the core network deviceaccording to claim 19, wherein the second identification information isthe same as information indicating the DN, the information having beenreceived from the UE for establishing the first PDU session.
 23. Thecommunication control method performed by the core network deviceaccording to claim 19, wherein the second identification information isequivalent to an Access Point Name (APN).
 24. The communication controlmethod performed by the core network device according to claim 19,wherein the core network device is able to perform transmitting andreceiving of user data by using the second PDU session after the secondPDU session is established.